Aircraft carrier operations during World War II
See also other articles in this series:
- Atlantic Theater aircraft carrier operations during World War II
- Pacific Theater aircraft carrier operations during World War II
- Carrier aircraft used during World War II
- Design and capability of aircraft carriers during World War II
- Lists of aircraft carriers operational during World War II
- Lists of aircraft carrier operations during World War II
Naval historians such as Evan Mawdsley, Richard Overy, and Craig Symonds concluded that World War II's decisive victories on land could not have been won without decisive victories at sea. Naval battles to keep shipping lanes open for combatant's movement of troops, guns, ammunition, tanks, warships, aircraft, raw materials, and food largely determined the outcome of land battles. Without the Allied victory in keeping shipping lanes open during the Battle of the Atlantic, Britain could not have fed her people or withstood Axis offensives in Europe and North Africa. Without Britain's survival and without Allied shipments of food and industrial equipment to the Soviet Union,[a] her military and economic power would likely not have rebounded in time for Russian soldiers to prevail at Stalingrad and Kursk.
Without victories at sea in the Pacific Theater, the Allies could not have mounted amphibious assaults on or maintained land forces on Guadalcanal, New Guinea, Saipan, The Philippines, Iwo Jima, or Okinawa. Allied operations in the Atlantic and Pacific theaters were interconnected because they frequently competed for scarce naval resources for everything from aircraft carriers to transports and landing craft. Effective transport of troops and military supplies between the two war theaters required naval protection for shipping routes around the Cape of Good Hope, through the Suez canal, and through the Panama Canal. In both theaters, maritime dominance enabled combatants to use the sea for their own purposes and deprive its use by adversaries. As naval historian Admiral Herbert Richmond stated, "Sea power did not win the war itself: it enabled the war to be won".
Aircraft carriers played a major role in winning decisive naval battles, supporting key amphibious landings, and keeping critical merchant shipping lanes open for transporting military personnel and their equipment to land battle zones. This is the main article of a series that covers World War II from the vantage point of aircraft carrier operations. (See also the other six articles listed above.)
Ascendancy of aircraft carriers over battleshipsEdit
It became apparent early in the war that control of the air was prerequisite for successful surface action both on land and at sea.[b] For much of the war, Britain and America fought mainly on the seas, where successful Allied naval operations permitted effective support and reinforcement of troops in North Africa, the Soviet Union, Western Europe and the Pacific. These operations also crippled similar efforts by Italy and Japan to sustain the empires they built by conquest. By 1942, aircraft carriers with the striking power provided by hundreds of warplanes delivering bombs and torpedoes to targets hundreds of miles away supplanted battleships with big guns as the principal warships around which navies assembled task forces for major campaigns.
Only America, Britain, and Japan made significant use of aircraft carriers during World War II.[c] The following table shows the number of each type of carrier the principal combatants operated that had at least one flight deck, was capable of both launching and recovering aircraft at sea, and that was operational sometime between July 1937 and August 1945. The counts include carriers in service before the war began as well as those commissioned during the war.
World War II fleet carriers typically displaced 20,000 to 35,000 tons and could sail at 30 to 35 knots. Japanese and American fleet carriers were typically capable of carrying 50 to 90 aircraft into combat. British carriers were designed with armored decks, a measure that provided significantly greater protection against bombs and kamikazes. The additional weight of the armor, however, reduced their typical carrying capability to 35 to 55 aircraft. Thus their additional defensive measures limited their offensive striking power until Britain introduced a new carrier class late in the war.
Light aircraft carriers were fast enough to keep up with the fleet carriers but their smaller size typically reduced their aircraft load to between 30 and 50. The design of those commissioned immediately after the war began typically reflected the immediate need for fast carriers and took advantage either of having other ship hulls available for conversion to aircraft carriers or the available capacity of commercial shipyards to build them. While these carriers made contributions to the war efforts, their relatively small size made them operationally inefficient. The measure of navel power in the Pacific Theater was the number of fleet carriers a navy had.
Escort carriers were smaller, slower, lightly armored, and carried 20 to 30 aircraft. They were not typically included with naval battle fleets, but before the war was over, escort carriers had performed every function that the larger carriers did.
Merchant aircraft carriers (MACs) transported grain and oil in the holds below the flight deck and carried 3 or 4 aircraft to protect themselves and other ships in convoys in which they traveled. None were used for offensive operations.
Land-based aircraft as well as carrier-launched aircraft fought at sea. In the Atlantic Theater, German and Italian aircraft attacked Allied convoys that were protected by fighter aircraft from Allied airfields as long as convoys were within fighter range. As carriers became available, Allied carrier-launched fighters provided protection in those ocean areas that could not be protected by land-based planes. In the Pacific Theater, Japan's successful expansion was typically achieved by progressively using land-based aircraft to support invasions of new areas that were within striking distance of airbases that they had established on previously conquered areas. For the Allies, land-based aircraft at local airfields contributed significantly to America's defense of Midway Island and Guadalcanal. Naval fighters and bombers that operated from land-based airfields were typically delivered to battle zones by aircraft carriers. In both theaters, carrier-launched aircraft played significant roles in dominating the air, and construction of aircraft carriers received priority.
At the same time that America, Britain, and Japan began emphasizing aircraft carrier construction, they de-emphasized construction of battleships. Before the war, the number of battleships a country operated was universally regarded as the principal indicator of naval power. Japan's raid on Pearl Harbor sank or damaged eight[j] of America's eighteen[k] battleships. America repaired and returned six of those eight battleships to service[l] but commissioned only eight new battleships during the rest of the war.[m] During the period September 1939 to August 1945, America commissioned ten new battleships while Japan commissioned only two and converted two existing ones to hybrid aircraft carriers. Britain commissioned five new battleships. Germany, Italy, and France together commissioned a total of six. All together, only 23 new battleships were added to combatants' fleets during the war years[n] compared to 55 new fleet and light carriers.
During the entire war, battleship guns sank only a single fleet carrier and a single battleship.[o] In comparison, carrier-launched aircraft damaged, sank, or took part in sinking 19 battleships.[p] Although Japan was first to recognize and exploit the greater effective striking power of aircraft carriers over battleships, she was slow to abandon employment of the latter. She commissioned battleships in 1941 and 1942 that were the largest and most heavily armed ever built.[q] After the losses at the Battle of Midway, however, Japan changed naval tactics and began leaving battleships out of major naval engagements. America began primary reliance upon its aircraft carriers for offensive operations early in the Pacific war out of necessity after the destruction of its Pacific battleship fleet during the Japanese raid on Pearl Harbor.
Functions performed by aircraft carriersEdit
Aircraft carriers were used for a wide variety of combat and combat support functions during the war. These included:
- Naval battles, during which carrier aircraft attacked each other and enemy warships, as they did during the Battle of Midway between American and Japanese fleets.
- Invasions, during which carrier aircraft provided support for amphibious landings and for occupying enemy-held positions by bombing those positions before, during, and after landings; spotting for warship guns, sometimes even controlling the firing; delivering replacement aircraft and aircrews to other carriers and to airfields after successful landings, as during the American invasion of Iwo Jima.
- Raids, during which carrier aircraft attacked enemy positions to degrade them but without the intention of landing and occupying those positions, as during the Japanese raid on Ceylon.
- Anti-shipping missions, during which carrier aircraft blockaded enemy ports or attacked enemy shipping and shipping facilities, as during the Allied attacks around Bodø, Norway.
- Anti-raider missions, in which carrier aircraft searched for and attacked enemy surface ships engaged in raiding enemy merchant shipping, as during the British sinking of the Bismark.
- Anti-submarine missions, during which submarine hunter-killer groups operating independently from convoys searched for and destroyed enemy submarines, as was accomplished by groups centered on USS Bogue during the Battle of the Atlantic.
- Convoy Escort, during which carrier aircraft searched for and attacked enemy aircraft and submarines that threatened a convoy's merchant ships, as when HMS Audacity accompanied Convoy HG 76 to Britain from Gibraltar.
- Transport, during which carriers delivered aircraft and aircrews to land bases or other carriers, as USS Long Island (CVE) did for Henderson Field on Guadalcanal and as the "CVE Plane Transport Unit" did during the invasion of Okinawa.[r]
- Training, during which carriers were dedicated to training pilots and/or conducting operating trials to improve carrier tactics and procedures. IJN Hōshō, HMS Furious, and USS Ranger spent long periods dedicated to training during the war.
- Repatriation, during which carriers, after the war, participated in returning military personnel to their home countries, as was done under America's Operation Magic Carpet.
The combatants differed in the functions they emphasized for carrier use, in part as a result of the challenges presented by their principal theater of operations. The table below indicates the percentage of carriers each combatant used for each function. For example, the US Navy operated a total of 33 fleet and light carriers during the war. Seventy-three percent of these carriers participated in naval battles at one time or another. Eighty-five percent were involved in support of invasions, etc. Escort carriers, although initially envisioned by many to perform only in support roles, ultimately performed all of the functions that the fleet and light carriers did
Percentage of Aircraft Carriers Performing Functions
|Carriers||Naval Battles||Invasions||Raids||Anti-Ship.||Anti-Raid.||Anti-Sub.||Convoy Escort||Trans.||Training||Repat.|
|CV & CVL|
Aircraft carrier contribution to Allied victoryEdit
Historian Craig Symonds lists three key factors enabling the Allies to win the war: British "grit", Russian manpower, and American industrial strength. Specifically, Britain continued alone in Europe against all odds for a year after the fall of France, stubbornly and successfully resisting the Axis. Thirty-five million Soviet Union soldiers fought during the war, as many as the United States, Germany, and Japan combined. The Soviet Union lost an estimated ten million soldiers to combat deaths, many more than any other combatant. America produced more artillery pieces, tanks, ships, and aircraft than all Axis countries combined,[s] including over 70% of the aircraft carriers commissioned during the war.
Historian Richard Overy points out that statistics demonstrating material superiority are not by themselves sufficient for explaining why the Allies won the war. Less easily quantifiable factors also played a significant part. The political will to fight and willingness of individual combatants to sacrifice was present within both the Allies and Axis. However, the timing of mobilizing manufacturing, technological, and manpower responses was also very important. America and Russia mobilized men and industrial capacity to rebound from significant military setbacks more quickly than anticipated by the attacking Axis powers. Important technological advances achieved by the Allies during the war outpaced those of the Axis powers in both offensive and defensive weapons systems. The Allies had greater and more strategically significant successes with code-breaking. The Allies placed greater emphasis than Axis powers on logistical support for men fighting on the front, enabling them to fight more efficiently and effectively. Geographical configurations, namely the English Channel, Atlantic Ocean, and Pacific Ocean, helped isolate British and American home bases from attack. Significant strategic offensive decisions by Axis leaders proved unsound, creating opportunities that the Allies.[t] Finally, luck played an important part in some decisive battles. Many of these factors played important parts in enabling the Allies to dominate the seas, a central reason, according to historian Evan Mawdsley, for their emerging victorious in the war. Nonetheless, while statistics relating to industrial capacity to produce arms and planes and ships do not tell the whole story, they remain an important part of it.
Successful Allied initiatives at El Alamein, Stalingrad, French North Africa, and Guadalcanal in November 1942 marked strategic shifts for World War II. Aircraft carriers contributed to the success of these operations by protecting convoys of armaments and other supplies to Egypt and Russia, keeping Malta supplied and able to disrupt Axis supply operations to North Africa, providing air support for troops during the invasion of North Africa, and by helping prevent Japanese troops and supplies from reaching Guadalcanal. Beginning in 1943, the extensive mobilization of American production capability for war resulted in dramatic increases in the number of carriers available for even more strategic initiatives. Overall, aircraft carriers contributed greatly to making 1942 the pivotal,turning point of the war, 1944 the decisive year, and 1945 one for essentially finishing up, albeit at great cost.
In the Atlantic Theater, successful transportation of troops, aircraft, tanks, oil, and food from or routed through North America or up the West African coast to Britain, Russia, North Africa, and continental Europe was essential for ultimate Allied victory. Allied aircraft carriers screened by corvettes, destroyers and destroyer escorts proved more successful and cost-effective than battleships or cruisers for protecting convoys from attacks by Axis submarines, raiders, and land-based aircraft. By mid-1943, the Axis threat of cutting essential Allied supply lines had passed. By this time, however, German battleships and submarines had sunk six British carriers[u]
In the Pacific Theater, a force of six Japanese fleet carriers with their combined aircraft striking power, the Kidō Butai, acted as a unit and roamed virtually at will for the first six months of the war. It made destructive raids against enemy positions from Hawaii in the east to India in the west and effectively supported Japanese invasions of the American Philippines, British Malaya and Burma, and the Dutch East Indies. Between May and October 1942, however, Japan and America fought four major battles between fleets centered around their aircraft carriers. During these battles, opposing warships never came within sight of each other nor fired their guns at other warships. Aircraft alone did the attacking. The first of these battles thwarted the Japanese attempt in the Coral Sea to isolate Australia. The second halted the expansion of Japanese control eastward in the Pacific toward Midway Island. The next two helped sustain the American presence on Guadalcanal. These four engagements[v] were costly for both sides. At the time Pearl Harbor was attacked, Japan had a total of nine fleet and light carriers in the Pacific Theater. America had four in the Pacific with another two far away in the Atlantic. At the end of October 1942, after battle attrition from sinkings and damages, Japan had only three such carriers operational in the Pacific Theater and America, for a two-week period, had none. Though costly,the battles were strategically advantageous for the Americans, contributing significantly to the shift of strategic initiative in the Pacific Theater from Japan to America.
America was better able make good on their losses from these battles. From October 1942 until the end of the Pacific war, America commissioned 26 new fleet and light carriers. Japan commissioned eight. Over the entire war, the Allies commissioned a total of 181 carriers of all types compared to Japan's total of 19.
|At September 1939||Comm. 1939-41||Sunk 1939-41||At December 1941[w]||Comm. 1942-45||Sunk 1942-45||Retired 1942-45||At September 1945||Total Comm.||Total Sunk|
Number of operational aircraft carriersEdit
The number of aircraft carriers operational for combat missions at any time was typically less than the total number of carriers afloat. For example, at the end of October 1942 following the Battle of the Santa Cruz Islands, only seven (47%) of the fifteen fleet and light carriers the combatants had afloat worldwide were operational. Japan had six such carriers afloat but only three were operational.[ac] America had three afloat, but one was in the Atlantic and the other two were damaged, leaving no operational carriers in the Pacific.[ad] Britain had six afloat, all in the Atlantic, but only three were operational.[ae] In short, although the Allies at that time had nine carriers afloat worldwide to oppose the six the Axis powers (Japan) had afloat, the combat operational reality in the Pacific was that, for a short period, there were zero Allied carriers that were operational to oppose Japan's three operational carriers.
|Total Afloat, 31 August 1939||7||5||6||18|
|Total Afloat, 31 October 1942||6||3||6||15|
|Non-Operational, 31 October 1942||-3||-2||-3||-8|
|Operational Worldwide, 31 October 1942||3||1||3||7|
|Operational Atlantic, 31 October 1942||-3||-1||0||-4|
|Operational Pacific, 31 October 1942||0||0||3||3|
- Details and sources are provided at Lists of aircraft carriers operational during World War II
As the war progressed, the relative number of operational carriers available for combat by each side depended upon 1)construction rates for new carriers, 2)losses due to sinkings, 3)how quickly carriers damaged in combat could be brought back into service, and 4)the time required for routine overhauls, refits for carriers to perform specific functions, and upgrades for older carriers. Short-term naval capabilities, plans, and outcomes were determined by the number of carriers that were operational during any given month. The impact of the relative number of operational, combat-ready carriers available was particularly felt during 1942, when the strategic initiative in the Pacific Theater passed from Japan to America.
Prior to 1936, international naval treaties negotiated in Washington in 1922 and London in 1930 had required that the total number of Japanese capital ships (battleships, battle cruisers, aircraft carriers) be less than the number operated by either America or Britain. The agreed upon ratio was 5:5:3 for Britain, America, and Japan respectively. Dissatisfied with these limitations, Japan discontinued participation in naval treaty negotiations in 1936 and invested in a construction program that within five years doubled the number of her fleet and light carriers. At the time of Japan's raid on Pearl Harbor and her invasion of British Malaya, Japan had almost as many such carriers afloat as Britain and America combined. Moreover, since the Allies deployed half of their carriers in the Atlantic Theater (including the Mediterranean) to oppose Germany and Italy, Japan had almost twice the Allies' number of carriers in the Pacific Theater (including the Indian Ocean) when she initiated hostilities.
Beginning in December 1942, the effects of America's industrial strength became evident as she began commissioning either a fleet carrier or a light carrier almost every month for the next two years. From November 1942, after the losses that year from four carrier battles, until the end of the war, America commissioned 26 new such carriers compared to 8 for Japan and 9 for Britain.
|From||March 1918||September 1939||December 1941||November 1942||March 1918|
|To||August 1939||November 1941||October 1942||September 1945||September 1945||Percent|
|Fleet & Light Carriers|
|Merchant Aircraft Carriers|
- Details and sources are provided at Lists of aircraft carriers operational during World War II.
Sea trials, delivery time, refittingEdit
Considerable time could elapse between a carrier's commissioning and becoming operational. After commissioning, carriers underwent sea trials to test the ship's systems and to train personnel. Upon satisfactory results, the carriers were then delivered to their intended war zones. This could involve weeks or months. In the case of HMS HMS Victorious (CV), she was chasing the German raider Bismark in the North Atlantic just weeks after commissioning and completion of final acceptance trials. For USS Essex (CV), however, sea trials and deploying her to the war zone in the Pacific took five months, and she did not see her first action until a raid on Rabaul eight months after commissioning.
The elapsed time between commissioning and combat action could also be short or long for escort carriers. Santee (CVE), a converted oil tanker rushed into service, still had workmen aboard during her shakedown cruise. Within seven weeks of commissioning, her aircraft were bombing airfields, spotting for warship's guns, patrolling for enemy cruisers and submarines, and refueling other ships in support of the invasion of North Africa. On the other hand, Empress (CVE), experienced one of the longest periods between commissioning and combat action. She was built in a West Coast US shipyard and then transferred to a Royal Canadian Shipyard on Canada's West Coast where she was commissioned in August 1943. She remained there until February 1944 during modifications to meet Britain's requirements for deployment to defend convoys. She then sailed to the Atlantic and participated in exercises with other escort carriers in the Caribbean. Aircraft were embarked for transport to Britain, where Empress arrived in April. There, through November, she underwent repairs for defects and modifications considered necessary based upon experience with other operational CVEs. Further preparations took place in December. In January 1945, still without aircrew aboard, she sailed for the Indian Ocean, where she took on an air squadron and participated in additional exercises in February. Thus about 18 months elapsed between commissioning and becoming operational in a war zone.
Escort carriers constructed in American shipyards and transferred to Britain spent more time being delivered because of the distance from America's west coast and Britain. In addition, modifications made in some cases because of concerns over onboard safety increased the elapsed time between CVE's commissioning and becoming operational. Britain made major changes to many American-made escort carriers due to concerns over fuel handling facilities after the unexplained explosion and consequent loss during refueling operations on Dasher in March 1943. In addition, some elapsed time was due to modifications to make some carriers suitable for specific combat functions. As lessons were learned during combat, carriers were refitted to change armament or otherwise reconfigure systems. Such modifications removed carriers from combat availability during these modifications. In short, long periods could occur between a carrier's being commissioned and its becoming operational for combat.
Damage to carriers due to weapons systems, collisions, weather, and other causes also reduced the number of carriers available for operations at any given time. Not every incident resulted in significant loss of combat effectiveness or retirement from combat.
In the early years of the war, the combatants risked and lost a high percentage of their carriers. By October 1942, after the carrier battles for the year, America, Britain, and Japan had, in both theaters, lost a combined total of 15 fleet and light carriers. With new commissionings, they then had 15 such carriers afloat compared with the 18 they had in August 1939 at the opening of the European war and 24 in December 1941 when Pearl Harbor was attacked. The following table shows the number of such carriers sunk each year of the war. The total number of escort carriers (CVE) sunk during the war is also shown.
|1939–1945 CV & CVL||5||5||16||26|
|1939–1945 CV, CVL, & CVE||12||8||21||41|
- Source: World War II Database Information for each carrier is available at Lists of aircraft carriers operational during World War II.
Percentage of time operationalEdit
Taking into account all the factors that kept aircraft carriers out of combat after commissioning, carriers generally were typically operational 80% to 90% of the time. They were typically out of service 5% to 15% for combat-related damage repair and 5% to 10% for delivery and refitting to otherwise improve performance. Royal Navy escort carriers were typically out of service for refitting more than other carriers.
|Fleet & Light Carriers||In Service||Damage Repair||Refitting||Total|
|RN Fleet & Light Carriers||79%||10%||11%||100%|
|USN Fleet & Light Carriers||82%||12%||6%||100%|
|IJN Fleet & Light Carriers||82%||15%||4%||100%|
|RN Escort Carriers||72%||5%||23%||100%|
|USN Escort Carriers||90%||5%||5%||100%|
|IJN Escort Carriers||82%||12%||6%||100%|
Carriers operational at the end of each monthEdit
The number of operational carriers available to the combatants at any point in time affected the capability, plans, and outcomes of military operations in both the Atlantic and Pacific theaters throughout the war. Taking into consideration the time for construction, shakedown trials, delivery, refitting, combat damage, and sinkings, the table below shows the number of fleet and light carriers that were operational for each combatant in each combat theater at the end of each month. The Pacific Theater includes the Indian Ocean and the Atlantic Theater includes the Mediterranean Sea.
The table capsulizes the course of the war for aircraft carrier operations. It reflects how Japan more than doubled the number of her carriers between leaving the Washington/London naval treaties in 1936 and the time she attacked Pearl Harbor in December 1941. It also reflects the attrition for carriers during the formative year of 1942. It reflects the industrial capacity of the United States, illustrating how she could make good her losses of 1942 while Japan could not. Finally, it reflects the shift of British carriers to the Pacific after the Allies prevailed in battles for Atlantic waters. Note also that, after mid-1942, the percentage of aircraft carriers afloat that were in fact available for combat operations was typically less than 70%. During the Guadalcanal campaign in 1942, that percentage fell below 50%. From then until mid-1944, Japan did not engage her carriers in a major operation. When at last she did, the rest of her carriers were sunk or damaged.
|Carrier Type:||CV & CVL||CV & CVL||CV & CVL||CV & CVL||CV & CVL||CV & CVL||CV & CVL||CV & CVL|
Atlantic Theater aircraft carrier operations during World War IIEdit
Details may be found at Atlantic Theater aircraft carrier operations during World War II.
Pacific Theater aircraft carrier operations during World War IIEdit
Details may be found at Pacific Theater aircraft carrier operations during World War II.
Carrier aircraft used during World War IIEdit
Details regarding carrier aircraft may be found at Carrier aircraft used during World War II.
Lists of aircraft carriers operational during World War IIEdit
Lists of aircraft carriers by carrier type for each country may be found at Lists of aircraft carriers operational during World War II.
Lists of aircraft carrier operations during World War IIEdit
Names, dates, and participating aircraft carriers for each military operation may be found listed chronologically at Lists of aircraft carrier operations during World War II.
Design and capability of aircraft carriers during World War IIEdit
Information about design and capability of carriers may be found at Design and capability of aircraft carriers during World War II.
- Britain and America shipped war-sustaining goods to the Soviet Union via Arctic Ocean, Persian Gulf, and Pacific Ocean routes.
- The effectiveness of carrier-launched aircraft against warships was demonstrated at the Battle of Taranto, the Attack on Pearl Harbor, and the destruction of Force Z.
- As of 2020, only nine countries have ever constructed aircraft carriers. (See Pike, p. ?)
- Excludes thirty-eight CVEs constructed in the US and transferred to Britain. Includes USS Langley, the first US aircraft carrier, that was reclassified as a seaplane tender before World War II began. She was used during the early months of the war to conduct anti-submarine patrols and ferry aircraft, just as an escort carrier would do. Because she still had a flight deck and could still transport, launch, and retrieve aircraft, Langley is included here as an escort carrier rather than a seaplane tender. (See Naval History Blog)
- Thirty-eight of these escort carriers were launched in the US and transferred to the UK under Lend-Lease.
- Includes as CVs both Hiyo and Junyo that are classified by some as CVEs. The displacements, length, speed, and number of aircraft for these carriers are intermediate between typical Japanese CVs and CVLs. Also, they were engaged in naval battles and supported invasions, unlike Japan's five CVEs, whose functions were limited to convoy escort, transportation, and training. After the losses at Midway, the IJN reorganized carriers into just two divisions, each consisting of two fleet carriers and one light carrier. Hiyo and Junyo were the fleet carriers for the IJN Second Carrier Division
- The Nisshin and the Mizuho are not included in the counts for this table. They could carry twenty-four seaplanes but did not have flight decks. They used catapults to launch aircraft and cranes to bring them back aboard.
- Ise and Hyūga are not included in the counts for this table. They were dreadnought class battleships rebuilt as hybrid aircraft carriers following Japanese fleet carrier losses during the Battle of Midway. Rear guns were removed to make room for catapults to launch seaplanes but there were no flight decks. Neither ship ultimately launched aircraft in combat during the war due to shortages of aircraft and pilots. Both were part of the Japanese decoy fleet during the Battle of Leyte Gulf.
- Includes only the Béarn. The Commandant Teste was initially a French seaplane carrier but later used as a training ship. She could carry twenty-six seaplanes but did not have a flight deck, instead launching planes by catapult and recovering them by crane. She was scuttled on 27 November 1942 to prevent her capture by the Germans.
- Sunk or damaged battleships were Nevada, Oklahoma, Pennsylvania, Arizona, Tennessee, California, Maryland, and West Virginia.
- Sixteen American battleships were commissioned between 1912 and 1923 (Wyoming, Arkansas, New York, Texas, Nevada, Oklahoma, Pennsylvania, Arizona, New Mexico, Mississippi, Idaho, Tennessee, California, Colorado, Maryland, and West Virginia) and two were commissioned in 1941 (North Carolina, and Washington.)
- Arizona and Oklahoma were not returned to naval service.
- Ten new USN carriers were commissioned during the war. South Dakota, Indiana, Massachusetts, Alabama, Iowa, New Jersey, Missouri, and Wisconsin were commissioned between 20 March 1942 and 16 April 1944. Carriers North Carolina and Washington were commissioned in 1941 before 7 December 1941.
- Between September 1939 and August 1945, 10 American (South Dakota, Indiana, Massachusetts, Alabama, Iowa, New Jersey, Missouri, Wisconsin, North Carolina and Washington), 5 British (Duke of York, King George V, Prince of Wales, Anson, Howe), 2 Japanese (Yamato, Musashi), 3 Italian (Vittorio Veneto, Littorio, Roma), 1 French (Richelieu), and 2 German battleships (Bismarck, Tirpitz) were commissioned. Construction of most of these had begun before the Japanese raid on Pearl Harbor.
- Guns from Kriegsmarine battleships Scharnhorst and Gneisenau sank the carrier HMS Glorious 8 June 1940 in the North Sea; battleship USN Washington sank battleship IJN Kirishima during the Naval Battle of Guadalcanal 14 November 1942. USN crusier gunfire may have contributed, along with bombing by carrier aircraft, to the sinking of IJN light carriers Chiyoda and Chitose 25–26 October 1944 during the Battle off Cape Engaño, part of the Battle of Layte Gulf.
- Carrier launched aircraft sank or damaged 19 battleships during World War II. These included nine American battleships, including the USS ‘’Utah’’ that was being used as a target ship, that were sunk or damaged during the Japanese raid on Pearl Harbor in 1941. All but USS Arizona and USS Oklahoma were salvaged and returned to service. Japanese battleships IJN Yamato, Musashi, Settsu (target ship), Ise, Hyuga, Hiei were damaged or sunk by American carrier aircraft, some with assistance by American submarines. KMS Bismarck was sunk by gunfire after being crippled by an aerial torpedo. KMS Tirpitz was damaged in repeated attacks British carrier aircraft and finally sunk in 1945 by British land based aircraft. Italian battleships RMS Conte di Cavour, Caio Dulio, and Littorio were sunk (then refloated) during the British raid on Taranto in 1940. An additional seven battleships were sunk by land based aircraft. HMS Prince of Wales and HMS Repulse were sunk by Japanese land based bombers in 1941. The German SMS Zahringen, in use as a target ship, was sunk by British land based bombers in 1944. RMS Roma was sunk by German land based aircraft in 1943. Greek ships Lemnos (formerly USS Idaho) and Kilkis (formally USS Mississippi) were sunk by German land based aircraft in 1941. The Russin battleship Petropavlovsk was sunk (later reflected) by German land based bombers in 1941.
- Japanese battleship Yamato and Japanese battleship Musashi, both with 18 inch guns.
- Task Unit 50.8.4 composed of USN escort carriers Attu, Admiralty Islands, Bouginville, and Windham Bay transported replacement aircraft and pilots to the fleet carriers and to combat-focused escort carriers. (See Y'Blood, Little Giants p. 351
- Only the Soviet Union produced more tanks and artillery pieces than the United States. Convoys to the Soviet Union protected in part by aircraft carriers provided a significant portion of the industrial equipment to manufacture those tanks and artillery pieces and provided food to sustain Soviet factory workers.
- Examples include Germany's shifting priorities during its Russian offenses of 1941 and 1942 and Japan's uncoordinated priorities leading to the attack on Midway Island in 1942.
- HMS Courageous (CV), HMS Glorious (CV), HMS Ark Royal (CV), HMS Audacity (CVE), HMS Eagle (CV), and HMS Avenger (CVE)
- The four carrier battles fought between American and Japanese fleets in 1942 were the Battle of the Coral Sea, the Battle of Midway, the Battle of the Eastern Solomons, and the Battle of the Santa Cruz Islands.
- Includes SPT USS Langley, CVE USS Long Island, CVE HMS Audacity, CVE HMS Archer, and CVE IJN Taiyo.
- Includes SPT USS Langley.
- Archer became a merchant ferry ship, Biter was retired, and Thane, after being hit by a torpedo, was written off as a total loss. Four Merchant Aircraft Carriers (Rapana, Amastra, Ancylus, and Acavus) were converted back to merchant ships.
- Excludes the French carrier Bearne.
- Excludes IJN Shōhō, commissioned 30 Nov 1941 and assigned to the Fourth Carrier Division of the 1st Air Fleet 22 December 1941. Its air group began training 4 January 1942. (See Kido Butai at combinedfleet.com)
- Includes Hosho (CVL) in use after October 1942 only for training. Also includes Junyo (CVL), Ryuho (CVL), and Katsuragi (CV), all of which at war's end were damaged and/or stripped of aircraft and air crews, stationary, and camouflaged in Japanese ports and in use principally as anti-aircraft platforms. Such carriers are not included as operational in the counts for the table, "Number Of Aircraft Carriers In Service At The End Of Each Month".
- Hosho, , Zuikaku, and Junyo were operational (Hosho only as a training ship) while Zuiho, Shokaku, and Hiyo were undergoing repair for combat damage. (See Tully, www.combinedfleet.com)
- Ranger was in the Atlantic, Saratoga was at Pearl Harbor undergoing repair for submarine torpedo damage, and Enterprise was in Noumea, New Caledonia, undergoing repair for extensive bomb damage sustained at the Battle of Santa Cruz Island. (See www.hazegray.org)
- Furious, Argus, and Formidable were operational. Illustrious was being refitted at Durban, South Africa, Victorious was being refitted in Britain, and Indomitable was undergoing repair in America for bomb damage sustained in the Mediterranean. (See Service Histories of Royal Navy Warships.)
- Excludes Hosho (CVL), Junyo (CVL), Ryuho (CVL), and Katsuragi (CV), all of which were "afloat" at the end of the war but not "operational" as aircraft carriers. They were damaged, stripped of aircraft and air crews, stationary, and camouflaged in Japanese ports in use principally as anti-aircraft platforms.
- Mawdsley 2019, p. 478; Overy 1995, p. 61; Symonds 2018, p. 641.
- Overy 1995, p. 18-19.
- Overy 1995, pp. 19, 254, 321; Mawdsley 2019, p. 478; Toland 1965.
- Baranov, Sergey (7 September 2011). "Campaign Summaries of World War 2, German U-Boats at War, Part 5 of 6, 1944". Naval History Homepage. Retrieved 11 February 2020.
- Hill, Alexander (July 2008). "Did Russia Really Go It Alone- How Lend-Lease Helped The Soviets Defeat The Germans". History.net. Retrieved 28 Aug 2019.
- Symonds 2018, p. xi-xii.
- Mawdsley 2019, pp. xxxix, 477.
- Symonds 2018, p. 268.
- Symonds 2018, pp. 402, 558.
- Overy 1995, pp. 18–19.
- Pike 2019, p. 164.
- Parshall & Tully 2005, p. 39.
- "Aircraft Carrier Operations During WW2", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 26 Mar 2021
- Parshall & Tully 2005, p. 418-19.
- Symonds 2018, pp. 372, 489.
- Symonds 2018, p. xvi.
- Frank 1990, p. 160.
- Y'Blood 1987, p. 327.
- "Aircraft Carrier Operations During WW2", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 26 Mar 2021
- "US Aircraft Carrier Functions", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 27 Mar 2021
- "UK Aircraft Carrier Functions", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 27 Mar 2021
- "Japanese Aircraft Carrier Functions", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 26 Mar 2021
- Symonds 2018, pp. 268, 641.
- Overy 1995, pp. 331–332.
- "Aircraft Carrier Operations During WW2", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 26 Mar 2021
- Overy 1995, pp. 2, 4.
- Overy 1995, pp. 314–325.
- Mawdsley 2019, p. xxxix.
- Toland 1970, p. 340.
- Mawdsley 2019, p. xxxvii.
- Symonds 2018, pp. 372, 553.
- Mawdsley 2019, p. xl.
- Mason, Geoffrey B. (10 October 2003). "HMS Victorious – Illustrious-class Fleet Aircraft Carrier". Service Histories of Royal Navy Warships in World War 2. Retrieved 2 February 2020.
- "Task Forces List". Naval War In Pacific 1941–1945, Ships Index. 2002. Retrieved 2 February 2020.
- "Santee". Dictionary of American Naval Fighting Ships. 1976. Retrieved 2 February 2020.
- Y'Blood 1983, p. 16–17.
- Mason, Geoffrey B. (15 October 2010). "HMS Empress (D 42) – Ruler-class Escort Aircraft Carrier". Service Histories of Royal Navy Warships in World War 2. Retrieved 2 February 2020.
- Mason, Geoffrey B. (2006). "HMS Dasher (D 32) – Avenger-class Escort Aircraft Carrier". Service Histories of Royal Navy Warships in World War 2. Retrieved 10 February 2020.
- "US Carrier Time Operational", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 27 Mar 2021
- "UK Aircraft Carrier Time Operational", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 27 Mar 2021
- "Japanese Aircraft Carrier Time Operational", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 26 Mar 2021
- "US Aircraft Carrier Operational Status By Month", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 28 Mar 2021
- "UK Aircraft Carrier Operational Status By Month", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 27 Mar 2021
- "Japanese Aircraft Carrier Operational Status By Month", World War II Database, C. Peter Chen, Lava Development, LLC, retrieved 26 Mar 2021
- Celander, Lars (2018). How Carriers Fought- Carrier Operations in World War II. USA & Great Britain: Casemate Publishers.
- Dull, Paul S. (1978). A Battle History of the Imperial Japanese Navy (1941–1945). Annapolis, Maryland: United States Naval Institute.
- Frank, Richard (1990). GuadalCanal- The Definitive Account of the Landmark Battle. New York, New York: Penguin Books.
- Hata, Ikuhiko; Izawa, Yashuho; Shores, Christopher (2011). Japanese Naval Air Force Fighter Units And Their Aces 1932-1945. London, England: Grub Street. ISBN 9781906502843.
- Helgason, Guðmundur. "uboat.net". Retrieved 4 April 2019.CS1 maint: ref duplicates default (link)
- Hermon, George (1968). "Volume II - Royal Australian Navy, 1942-1945". Retrieved 30 December 2018.
- Mason, Lt Cdr Geoffrey B., RN (2010). "Service Histories of 1,000 Royal and Dominion Navy Warships, including British Ships manned by Allied Navies". Naval History- World War 2 at Sea. Retrieved 3 April 2019.
- Morison, Samuel Eliot (1963). The Two-Ocean War- A Short History of the United States Navy in the Second World War. Boston, Massachusetts: Little, Brown and Company. ISBN 0-316-58352-9.
- Mawdsley, Evan (2019). The War For The Seas- A Maritime History of World War II. New Haven Connecticut: Yale University Press. ISBN 978-0-300-19019-9.
- Overy, Richard (1995). Why The Allies Won. New York, New York: W.W. Norton & Company. ISBN 0-393-03925-0.
- Parshall, Jonathan; Tully, Anthony (2005). Shattered Sword. USA: Potomac Books.
- Pike, Francis (2019). Hirohito's War- The Pacific War 1941–1945. London: Bloomsbury Achidemic. ISBN 978-1-4725-9671-0.
- Roskill, Stephen (1960). The Navy At War 1939–1945. Chatham, Kent, Great Britain: Mackays of Chatham. ISBN 1-85326-697-3.
- Symonds, Craig L. (2018). World War II At Sea. New York, New York: Oxford University Press. ISBN 9780190243678.
- Toland, John (1965). The Last 100 Days. New York, New York & Toronto, Canada: Bantam Books. p. 102. ISBN 0-553-34208-8.
- Toland, John (1970). The Rising Sun – The Decline and Fall of the Japanese Empire 1936–1945. New York, New York: Random House.
- Toppan, Andrew (2003). "Haze Gray and Underway- Naval History and Photography". Haze Gray and Underway. Retrieved 4 April 2019.
- Tully, Anthony (2018). "Kido Butai!- Stories and Battle Histories of the IJN's Carrier Fleet". Retrieved 4 April 2019.
- Whitehouse, Arch (1962). Squadrons of the Sea. New York, New York: Curtis Books- Modern Library Editions Publishing Company.
- Y'Blood, William T. (1983). Hunter-Killer US Escort Carriers in the Battle of the Atlantic. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-286-9.
- Y'Blood, William T. (1987). The Little Giants – U.S. Escort Carriers Against Japan. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-275-3.
- "Naval History and Heritage Command". U.S. Navy. 2019. Retrieved 3 April 2019.
- "Naval War In The Pacific 1941-1945- Ships Index". Naval War In The Pacific 1941-1945. Retrieved 4 April 2019.
- "NavSource Naval History – U.S. Naval Chronology of World War II". 2019. Retrieved 4 April 2019.
- "Pocket Sized Aircraft Carriers- Merchant hulls into Warships". Royal Navy Research Institute. 2019. Retrieved 3 April 2019.
- "World War II Database". Lava Development. 2019. Retrieved 4 April 2019.
- "WW2 Aircraft Carriers". Military Factory. 2019. Retrieved 4 April 2019.
- All Country's Carrier Histories (ww2db)
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