Government and military
Air Force investigations, bases and aircrew reports, from Project Sign to today. 221 events, newest first.
Government27 Apr 1949
The National Military Establishment released a digest of Air Materiel Command studies of more than 240 U.S. and 30 foreign reports. About 30 percent had been explained, visits from space were called highly improbable, and the memo said the sightings were neither a joke nor cause for alarm.
Government11 Feb 1949
The Air Force renamed Project Sign as Project Grudge, a scaled-down successor that treated most reports as misidentifications. Its 1949 report concluded sightings came from misread natural objects, hoaxes or psychological causes.
Photo: US Air Force, Public domain
Government31 Jan 1949
A confidential FBI San Antonio memo to J. Edgar Hoover, filed under 'Protection of Vital Installations', said the Army and Air Force treated flying saucer reports as a top-secret matter and that recent sightings were concentrated near the Atomic Energy Commission site at Los Alamos.
Military1949
Astronomer J. Allen Hynek reviewed the 237 reports gathered by the Air Force's Project Sign. His final report attributed about a third to astronomical causes such as planets and meteors, about a third more to balloons, rockets, flares or birds, and left about a fifth unidentified.
Photo: US Air Force, Public domain
Government10 Dec 1948
A Top Secret Air Force and Navy intelligence study reviewed about 210 sighting reports. It found something was being seen but its nature was unknown, and said that if the objects were foreign, a Soviet source would be most logical. Copies survived a 1950 order to destroy it.
Military5 Dec 1948
From late 1948, pilots, security staff and others near Albuquerque and Los Alamos reported bright green fireballs. Meteor expert Lincoln LaPaz doubted they were ordinary meteors; the Air Force's Project Twinkle camera effort photographed nothing and faded out.
Military4 Nov 1948
A top secret U.S. Air Forces in Europe intelligence cable reported recurring saucer sightings, including an object over Neubiberg Air Base, and relayed Swedish officers' view that some reflected advanced technology. The Pentagon included it in its May 2026 UFO records release.
Photo: USAAF, United States Air Force Historical Research Agency, Maxwell AFB Alabama., Public domain
Sightings24 Jul 1948
Eastern Air Lines pilots Clarence Chiles and John Whitted reported a glowing, wingless, cigar-shaped object with rows of lit windows passing their DC-3 near Montgomery at about 2:45 a.m. Ruppelt said it prompted the Air Force's 1948 'Estimate of the Situation'; the case was later relabeled a meteor.
Photo: Lestocq, CC BY-SA 4.0
Government1948
In early 1948, Air Force officers from Wright-Patterson asked J. Allen Hynek, director of Ohio State's McMillin Observatory, to help Project Sign find which saucer reports were astronomical. Hynek, then a skeptic, had no role in Grudge but returned as Blue Book's consultant from 1952 to 1969.
Photo: United States Government, Public domain
Military1948
Large plastic Skyhook research balloons, about 100 feet across, were flown in secret for the Navy, unknown to most Air Force pilots. Blue Book chief Edward Ruppelt and the Condon report later cited them as the likely cause of many reports, including Capt. Thomas Mantell's fatal 1948 chase.
Photo: US Navy, Public domain
GovernmentDec 1947
The Air Force's first formal study of flying-saucer reports, run by Air Materiel Command at Wright Field. It ran until early 1949, when Project Grudge replaced it.
Photo: US Air Force, Public domain
Government23 Sep 1947
Lt. Gen. Nathan Twining, head of Air Materiel Command at Wright Field, wrote to Army Air Forces headquarters that the disc reports described something real, not imagined, and urged a classified, prioritized study. That study began months later as Project Sign.
Photo: U.S. Air Force, Public domain
Government30 Jul 1947
At the request of Army Air Forces intelligence, FBI headquarters told its field offices to check each flying-disc sighting brought to them and judge whether it was genuine, imagined or a prank. By July 1950 the FBI said the Air Force had taken over and it no longer investigated such reports.
Photo: FBI, Public domain
Government30 Jul 1947
At the request of Army Air Forces intelligence, the FBI told its field offices to check each flying disc sighting brought to them. Director J. Edgar Hoover wanted agents able to examine any discs recovered. The FBI handed the work back to the Air Force in July 1950.
Photo: FBI.gov, Public domain
Military16 Jul 1947
A Fourth Air Force intelligence memorandum dated July 16, 1947 recorded a July 12 interview with Kenneth Arnold in Boise. The interviewer judged that Arnold saw what he described and found his distances consistent with aeronautical charts; copies went to the FBI.
Photo: Associated Press, Public domain
Military8 Jul 1947
Roswell Army Air Field announced it had recovered a "flying disc" from a nearby ranch, and the Army said the next day it was a weather balloon. A 1994 Air Force report concluded the debris most likely came from Project Mogul, a then-secret balloon program.
Photo: Roswell Daily Record, Public domain
Government8 Jul 1947
An FBI Dallas teletype relayed what Eighth Air Force headquarters told agents about the object recovered near Roswell: a hexagonal object hung from a balloon that resembled a high-altitude weather balloon with a radar reflector, being flown to Wright Field for examination.
Photo: Roswell Daily Record, Public domain
Military8 Jul 1947
Test pilots, officers and a crew of technicians at Muroc air base in California's Mojave Desert reported round, silvery objects on the morning of July 8, 1947. Edward Ruppelt, later head of Project Blue Book, wrote that this was the first sighting to make the Air Force take a deep interest.
Photo: U.S. Navy, Public domain
Sightings4 Jul 1947
During the July 1947 wave, Portland police officers, a harbor patrol crew and residents reported groups of fast, wobbling disks over the city, with sheriff's deputies across the river in Vancouver, Washington, reporting more. Ruppelt summarized the reports from Air Force files.
Sightings24 Jun 1947
Private pilot Kenneth Arnold reported nine fast objects flying in formation near Mount Rainier. Press coverage of his account set off the first U.S. wave of flying saucer reports, and the Air Force later carried the case as unexplained.
Photo: Kenneth Arnold, Public domain
SightingsJun 1947
Two Tacoma men claimed six doughnut-shaped objects appeared over Puget Sound and one dropped slag-like debris. Two Army Air Forces intelligence officers who looked into it died when their B-25 crashed on the way back. Ruppelt said the official report concluded the men admitted it was a hoax.
Photo: Mark Yasuda, CC BY-SA 4.0
