DOW-UAP-D100, Air Materiel Command Report on Unidentified Flying Objects, 1947-1948
According to the releasing agency, this file is a collection of U.S. Government memoranda and correspondence concerning 'Project Sign,' a 1948 U.S. Air Force program to investigate reports of high-performance airborne objects. The Air Force characterized some reports as consistent with 'real' objects rather than fabrications or perceptual errors, citing reported high speed and maneuverability as exceeding known performance envelopes of U.S. military aircraft and thus a potential national security threat if validated. This prompted the Air Force to call on the Air Materiel Command (AMC), the Service's Major Command for logistics and procurement from 1946 to 1961, to gather further evidence, noting an 'imperative need' for such evidence amid the early Cold War strategic environment. The correspondence includes a memo on 'Flying Object Incidents in the United States' addressed to the Commanding General, Air Materiel Command, Wright-Patterson Air Force Base, referencing a letter dated 30 December 1947 from the Director of Research and Development, Headquarters USAF, that required establishment of Project Sign. The memo concludes it is 'inescapable that some type of flying object has been observed,' that origin was not discernible, and that determining whether objects were of domestic or foreign origin must be increased. It also addresses growing press interest and the possible need for an official public statement. Per the releasing agency, AMC's investigation found observers were generally not mistaken in reporting an airborne object, but characterizations as unusual likely reflected the 'limits of their personal experience'; many rounded objects were identified as weather or upper-air scientific balloons, several as celestial phenomena such as Venus, and a small number lacked a 'reasonable everyday explanation.'
Description
Declassified U.S. Government memoranda and correspondence relating to Project Sign, the 1948 U.S. Air Force program tasking the Air Materiel Command at Wright-Patterson AFB to investigate reports of high-performance airborne objects, released by the Department of War in 2026.
Claims
The correspondence concludes that 'some type of flying object has been observed,' though its identification and origin were not discernible to the Headquarters.
85%There was an 'imperative need' for evidence to determine whether the objects were of domestic or foreign origin so that appropriate countermeasures could be taken.
85%AMC assessed that observers generally did see real airborne objects but that unusual characterizations reflected the 'limits of their personal experience.'
80%AMC identified many rounded objects as weather or upper-air scientific balloons and several as celestial phenomena such as Venus.
80%A small number of reports lacked a 'reasonable everyday explanation.'
75%AMC identified many reported rounded objects as weather or upper-air scientific balloons and several as celestial phenomena such as Venus.
70%Some type of flying object has been observed, and its identification and origin were not discernible to the Air Materiel Command headquarters.
60%Reported characteristics such as high speed and maneuverability exceeded known performance envelopes of U.S. military aircraft, presenting a potential national security threat if validated.
55%A small number of reports lacked a reasonable everyday explanation.
55%
Events
Dec 29, 1947
Letter establishing Project Sign
Letter from Director of Research and Development, Headquarters USAF, requiring establishment of Project Sign.
Dec 31, 1947
Air Materiel Command investigation of flying object incidents
AMC investigation of reported high-performance airborne objects over the United States.
Aug 6, 2026
Public release by Department of War
Declassified file released on the war.gov UFO portal.
Dec 29, 1947
Directive establishing Project Sign
Letter from the Director of Research and Development, HQ USAF, requiring establishment of Project 'Sign.'
—
Flying Object Incidents in the United States (Project Sign investigation)
Air Materiel Command investigation into reports of high-performance airborne objects.
Aug 6, 2026
Department of War release
Public release of the declassified file via war.gov.
Dates mentioned
Keywords
Entities
Extracted text (OCR)
5 re fle arate AFODI/iaj Gen ender t/non/sttara- er ad” SUBJECT: Flying Object Incidents in the United states Tor Comanding General, Air Satoriel Command Wright-Pattersm Ar Poree Base Dayton, dhio L hoy. £099 Dassafeid Pleo 1, By letter dated 80 Decenber 1947 from the Director of Research and Developsont, Headquarters USAP, your Headquarters was required to establish Project "sia". 2 2, The conclusion appears inescapable that sone type of flying object has been observed. Identification and the origin of these objecta ie not discernible to this Headquarters, It is Amperative, therefore, that efforts to determine whether thei objects are of donestic or foreign origin must be increased until conclusive evidence is cbtained. The needs of national 4 require such evidence in order that appropriate counterneasure may be taken. ee 3. In addition to the imperative need for evidence to permit sity of informing the public as to the status of }0 date there has been too little date to present to the public. The press, however, is about to take it into its on hands and denand to be told what we do or do not know about the situation. Silence on our part will not long be accept- able. 4. Request immediate information as to your conclusions to date and your recomendations as to the information to be given to the press. Your recommendation is requested also as to whether that information should be offered to the press or with= held until it is actively sought by the press. BY COMMAND OP THE CHIEF OF STAFF: iat A aie — eeeaiige seen SA Major Oonerals USF crete of Barectar of Thuel icone, One
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Connected through the network
SF-2026-001137