Documents / Report
This U.S. Air Force Project SIGN file from 1947 and 1948 collects correspondence on unidentified flying objects. In it, Headquarters USAF asks Air Materiel Command for its conclusions, and AMC replies on 8 November 1948 after studying about 180 incidents. AMC concludes that observers saw real flying objects but that there is no proof they are aircraft, and it advises against briefing the press. The file also includes letters to the CIA, a citizen's inquiry, a request for a Rand spaceship study and an intelligence analysis of 1947 sightings.
From the source:Release of 2026-08-07 Incident: 1947-1948, N/A. This file is a collection of U.S. Government memoranda and correspondence relating to “Project Sign,” a 1948 U.S. Air Force program to investigate reports of high-performance airborne objects. The documents characterize some of these reports as being consistent with “real” objects rather than fabrications or resulting from perceptual errors. The U.S. Air Force cites the reported characteristics of the phenomena, e.g., high speed and maneuverability, as exceeding known performance envelopes of U.S. military aircraft and thereby presenting a potential national security threat, if validated. This potential threat 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 to assess the validity of the reports. The Air Force emphasized that there was an “imperative need” for such evidence to enable appropriate countermeasures. The stated urgency of this request reflects the strategic environment of the early Cold War, a period characterized by heightened national defense concerns amid rapid global advancements in aerospace design and development. In framing the call for an investigation, the Air Force noted that sustained public interest and persistent inquiries from the press may eventually require an official statement in response. AMC’s investigation found that observers were generally not mistaken when reporting that they had seen an airborne object, but that their characterizations of those objects as unusual was likely a reflection of the “limits of their personal experience.” It identified “a great many” of the objects reported with a rounded appearance as “weather or upper air scientific balloons of some type.” It also identified several cases in which the reported objects were most likely celestial phenomena, such as Venus. AMC found that a small number of reports lacked a “reasonable everyday explanation,” but that “so far, no physical evidence of the existence of the unidentified sightings has been obtained.” AMC expressly considered whether the phenomena may have been “vehicles from another planet,” but found no evidence supporting such an origin. Ultimately, AMC found that “there is as yet no conclusive proof that unidentified flying objects, other than those which are known to be balloons, are real aircraft.” In light of these findings, AMC recommended that the Department of War should avoid publicly commenting on the subject of “flying discs.” Responding to the Air Force’s anticipated concerns regarding public interest in the subject, AMC recommended that the Department should reply in terms that minimize the investigation’s inconclusive findings, focusing on positive determinations in cases assessed to be weather balloons and celestial phenomena.
“Headquarters”26 pages
COP Y HEADQUARTDS FOURffl AIR FORCB Office of the Assistant Chief of Staff, A-2 Intelligence Hamilton Field, California 4AFDA-3/1208-I Uar 11, 1948 SUJ1TECT: lnvestigation of Flyine; Disc. TO: Chief of Staff United States Air Forces Washington, D. c. ATTN: Directorate of Intelligence Air Intelligence Requirements Division 1. Incident reported on 9 March 1948, this headquarters, per telephone call from SEt- A. M. Larsen, Sheriff's office, Bakersfiel d, California. a . Observation by Mr. Les Buchner, Bakersfield, California, of two objects f alling to earth from unknown source on 5 March 1948 between 1610 and 1655 hours . Description of objects similar to falling aircraft with smoke and debris trailing. Observation made at Bakersfield with objects sighted sout hwest toward Buena Vista Lake , California. b. Observation by llr . Denio, employee of the Pacific General Electric Compaey, .Bakersfield, California, of two objects which fell to earth from unknown source north of Bakersfield, California, 8 March 1948. One object seemed to be on fire with red and black smoke trailing behind. 2. Informant La.rser. stated that searching parties, aircraft and rescue units have made numerous attempts to locate t hese reported objects without success. 3. Investigation of incident has been initiated by this headquarters. Report will follow . /S/ DONAIJ) L. SPRINGER Lt . Colonel, USAF AC of S, A-2 Information to: ADC, W.tchel Fld, B.Y. l"BI, San Francisco G-2, Sixth Army DIO, San Francisco (12th Nav. Dist)
Report, from the pursue collection. The PDF is mirrored here; the original link is above. 245 pages are in the text index: search them above, or from the library's search.