Project Sign

Project Sign was an official U.S. government study of unidentified flying objects (UFOs) undertaken by the United States Air Force (USAF) and active for most of 1948. It was the precursor to Project Grudge.


The project was established in 1948 by Air Force General Nathan Farragut Twining, head of the Air Technical Service Command, and was initially named Project SAUCER.[1] The goal of the project was to collect, evaluate, and distribute within the government all information relating to UFO sightings, on the premise that they might represent a national security concern.[1]

At first the project hypothesized the sightings might be Soviet secret weapons.[1] However, Project Sign's final report, published in early 1949, stated that while some UFOs appeared to represent actual aircraft, there was not enough data to determine their origin.[2] Almost all cases were explained by ordinary causes, but the report recommended a continuation of the investigation of all sightings.[1]

Project Sign was first described in the 1956 book The Report on Unidentified Flying Objects by retired Air Force Captain Edward J. Ruppelt who later directed Project Grudge and Project Blue Book. In this he also claimed that Sign had produced an "Estimate of the Situation" which endorsed an interplanetary explanation for UFOs, but General Hoyt Vandenberg, Chief of Staff of the Air Force, shut down Project Sign for lack of proof.[3] No copy of this document or any other corroboration of Ruppelt's claim has been produced, and Popular Mechanics called the report "probably more mythological than real".[4]

Project Sign was followed by Project Grudge after a conclusion was reached that evaluations of UFOs were a necessity of military intelligence in a post-war climate.[5]

Caldwell investigationEdit

In May 1949, officers of Project Sign received a letter from a aeronautical company shareholder, who explained that the company had been building aircraft similar to the "flying saucers" which were then a popular topic in the press. This was during the UFO craze following Kenneth Arnold's reports of seeing UFOs over Mount Rainier and the Roswell Incident that followed. The Air Force had canvassed for reports of flying saucers, and the shareholder apparently felt that inventor Jonathan Edward Caldwell's disk-rotor might explain them.

Tracking down the leads, the team, accompanied by the Maryland Police, visited an abandoned farm in Glen Burnie, Maryland (outside Baltimore), where the damaged remains of Caldwell's disk-rotor aircraft were discovered. They also tracked down Driggers, who told them the story of the attempted flight in 1937/8. The team reported that the prototypes could not be responsible for the "flying saucer" reports that were being received from all around the country.[6]

Photographs of the broken disk-rotor machine continue to appear in UFOs books to this day. They were often described as "crashed" flying saucers in earlier works, claiming it was one more example of the USAF being in possession of such vehicles. More recently they are normally connected with the claims that the Nazis had built working flying saucers late in the war, lumped together with other disk-shaped aircraft like the Avrocar, Arthur Sack A.S.6 and Vought V-173, in an effort to demonstrate that such aircraft were both possible and well-researched.[7]


  1. ^ a b c d "CIA's Role in the Study of UFOs, 1947-90 — Central Intelligence Agency". Retrieved 2020-04-30.
  2. ^ Blum, Howard, Out There: The Government's Secret Quest for Extraterrestrials. Simon and Schuster, 1990
  3. ^ Ruppelt, Edward J (1960). The Report on Unidentified Flying Objects (2nd ed.). Doubleday & Company.
  4. ^ Banias, M. J. (2019-12-17). "50 Years Ago, the Air Force Tried to Make UFOs Go Away. It Didn't Work". Popular Mechanics. Retrieved 2020-05-03.
  5. ^ Project Blue Book : the top secret UFO files that revealed a government cover-up. Steiger, Brad. Newburyport, MA. 2019. ISBN 978-1-59003-300-5. OCLC 1078162415.CS1 maint: others (link)
  6. ^ Just old contraptions, "Flying Saucers" find proves false alarm, The Los Angeles Times, August 21, 1949
  7. ^ "An Aeronautical History of Flying Saucers". Archived from the original on 2010-12-17. Retrieved 2011-02-11.

Further readingEdit

External linksEdit

Preceded by
US military projects investigating the UFO phenomenon Succeeded by
Project Grudge