Cases where a specific conventional explanation has been proposed but is contested by witnesses, investigators or the evidence - or where only part of the case has been explained.
69 documented cases currently classed as disputed, spanning 1897 to 2025. 39 of them involved military witnesses or sensors. 43 have declassified government records, with 98 source documents linked in total.
Highest-credibility cases: USS Roosevelt Gimbal/GoFast Encounters (2015, scored 10/10), GoFast Video (2015, scored 9/10) and Chilean Navy Helicopter UFO (2014, scored 9/10).
How a case is classed: resolution criteria
Peer-reviewed Nature study found statistically significant correlations between 1950s sky anomalies, nuclear weapons testing, and UAP reports at Palomar Observatory.
Unidentified objects forced a police helicopter into emergency evasive action over US air bases in England, with 20+ objects reported over three nights.
Thousands witnessed unidentified drone-like objects over New Jersey and the Northeast near military installations, triggering national alarm before partial official explanations.
Unidentified objects shut down Tianjin's international airport for three consecutive nights, grounding flights and prompting fighter jet scrambles across China.
Night vision footage from the USS Russell showed pyramid-shaped objects hovering over Navy destroyers during multi-ship encounters the Pentagon confirmed as genuine.
A Navy F/A-18 ATFLIR pod captured a small, fast-moving object skimming over the ocean — one of three officially released Pentagon UFO videos.
Navy pilots from the USS Roosevelt captured the Pentagon-confirmed 'Gimbal' and 'GoFast' infrared videos of objects displaying anomalous flight characteristics.
A Chilean Navy helicopter captured 9 minutes of infrared video showing an unidentified object expelling unknown material, which Chile's official UAP agency could not explain after 2 years of analysis.
A US Customs aircraft captured IR video of an object entering the ocean and splitting in two near Puerto Rico, analyzed in a 160-page scientific report.
Dozens of Texas residents observed a massive silent craft with military jets in pursuit, later confirmed by radar data showing the object near the presidential ranch.
A Mexican Air Force surveillance plane recorded 11 objects on FLIR and radar that were invisible to the naked eye - and Defense Minister Gen. Vega García released the footage on Mexican TV in May 2004, the first state-sanctioned military UAP video release in the Americas.
Thousands of witnesses including Arizona's governor observed a massive silent V-shaped craft and stationary orbs over Phoenix in one of the most witnessed UFO events ever.
Three women encountered a strange being in daylight in Varginha; military reportedly captured creatures, and a policeman who handled one died weeks later.
Military personnel at two RAF bases observed a massive triangular craft with a searching beam of light; investigated by the MoD's Nick Pope.
Thousands filming a solar eclipse over Mexico City independently captured footage of a metallic disc, creating one of the most widely filmed UFO events.
Two hikers photographed a diamond-shaped craft with a Harrier jet nearby in Scotland. The UK government classified the photos for over 30 years before one was released in 2022.
Over 13,500 witnesses across Belgium reported massive silent triangular craft, confirmed by police, radar, and Belgian Air Force F-16 intercepts.
Bob Lazar claimed to have reverse-engineered alien propulsion at 'S-4' near Area 51, describing Element 115 fuel years before its synthesis.
Builder Ed Walters captured extensive UFO photographs in Gulf Breeze, FL while hundreds of independent witnesses reported sightings during a months-long wave.
A JAL 747 captain encountered a walnut-shaped object 'twice the size of an aircraft carrier' over Alaska, tracked on radar; FAA evidence was confiscated by CIA.
Thousands reported a massive silent boomerang craft over the Hudson Valley for four years, documented in over 5,000 sighting reports.
US Air Force personnel at a NATO base in England reported close encounters with a triangular craft over multiple nights, supported by physical evidence and an official memo.
A Spanish airliner with 109 passengers made an emergency landing at Valencia after being shadowed by two bright objects; the Spanish Air Force scrambled a Mirage F1 that could not catch them - and the MoD's 1992 declassified file confirms the radar tracks.
A TV film crew captured footage of luminous objects simultaneously tracked on Wellington radar off New Zealand's coast, investigated by the RNZAF.
RCMP Constable James Blackwood and twelve witnesses observed an oval craft with a fin hovering over water for two hours near Clarenville, which mimicked the flashing lights of his police cruiser.
Iranian Air Force F-4 Phantoms scrambled to intercept a UFO over Tehran experienced weapons and electronics failures, documented by a declassified DIA report.
Logger Travis Walton was struck by a beam from a hovering disc and vanished for 5 days; six coworkers who witnessed the event passed polygraph tests.
An alleged midair collision between a small plane and a UFO near Coyame, Mexico, reportedly led to a covert U.S. military crash retrieval operation.
A seismic event, explosion, and glowing object on the Berwyn Mountains created the 'Welsh Roswell,' with allegations of military crash retrieval.
A US Army helicopter was pulled upward 2,100 feet by an unknown force while a cigar-shaped object bathed it in a green beam, confirmed by ground witnesses.
Two fishermen reported abduction by robotic beings; a secret sheriff's recording captured their genuine terror when they believed they were alone.
Three NASA astronauts aboard Skylab 3 observed and photographed a bright red rotating object from orbit for over 10 minutes, with NORAD unable to identify any known object in the vicinity.
On December 11, 1972 the Apollo 17 crew described 'jagged angular fragments' tumbling past the spacecraft windows - 'the Fourth of July out of Ron's window.' The Pentagon re-classified the photographs from 'insulation' to 'potentially physical object' on May 8, 2026.
A teenager witnessed a glowing object that left a hydrophobic ring in the soil with anomalous chemical properties persisting for years.
Apollo 12 photographs of bright unidentified objects above the lunar horizon were re-classified by the Department of War on May 8, 2026 from 'photographic artifact' to 'potentially the result of a physical object.'
Apollo 11 crew observed a luminous object pacing their spacecraft during translunar coast; the apocryphal 'they're warning us off' Armstrong transmission is the most-repeated UFO claim of the lunar era.
Future U.S. President Jimmy Carter and ten witnesses observed a color-changing luminous object over Leary, Georgia, making it the only confirmed UFO sighting by an American president.
A B-52 crew and ground personnel at Minot AFB simultaneously tracked a large luminous object on radar that disrupted UHF communications near nuclear missile sites.
A glowing UFO hovered over Malmstrom AFB while 10 Minuteman nuclear missiles simultaneously went offline with no technical explanation found.
Four police officers across two states chased a luminous UFO for 86 miles; Blue Book's 'Venus' explanation was rejected by its own scientific consultant.
Over 200 students and teachers at a Melbourne school witnessed a silvery disc land in an adjacent field before authorities allegedly suppressed the story.
A controlled fireball landed near Kecksburg, PA; witnesses described an acorn-shaped craft with hieroglyphics before the Army removed it under secrecy.
An Air Force tracking-station film of a 1964 Atlas-F missile test reportedly captured a disc-shaped object firing four light-flashes that knocked the dummy warhead off-trajectory - one of the foundational nuclear-UAP-interaction cases.
A photograph taken of a young girl on a marsh appeared to show a figure in a white spacesuit behind her. Kodak verified the negative was genuine and unaltered.
The first widely publicized alien abduction case in the US, featuring missing time, hypnotic regression, and the iconic Betty Hill star map.
Anglican priest and 37 witnesses observed a hovering disc with humanoid figures who appeared to wave back when greeted, over a Papua New Guinea mission station.
Nine hikers died under bizarre circumstances in the Ural Mountains; the lead investigator believed the deaths were connected to reported luminous objects in the area.
A photographer aboard a Brazilian Navy ship captured photos of a Saturn-shaped UFO over Trindade Island, endorsed by the Navy and the President of Brazil.
At least 15 independent witnesses near Levelland, TX reported a glowing object that killed vehicle engines and headlights at close range.
A USAF RB-47 reconnaissance bomber tracked an object on radar, electronic countermeasures, and visually for 700+ miles across multiple states.
The Sutton family reported hours-long siege by small luminous beings at their Kentucky farmhouse, prompting a multi-agency investigation.
An entire Serie A football match in Florence stopped when ~10,000 spectators watched cigar-shaped craft cross the sky and 'angel hair' fibers fell on the stadium - University of Florence chemists analyzed the residue.
During NATO's first major maritime exercise, US, UK, Danish, and other allied crews logged multiple radar+visual UFO sightings across the North Sea - one of the earliest multinational military UAP clusters.
A group in Flatwoods, WV encountered a tall hissing entity near a glowing landed object, leaving witnesses physically ill during the 1952 UFO wave.
UFOs tracked on radar over the nation's capital on two consecutive weekends, triggering jet scrambles and the largest Pentagon press conference since WWII.
Navy photographer Delbert Newhouse filmed bright maneuvering objects over Utah; Navy analysis concluded they were 'intelligently controlled vehicles.'
V-formations of bluish-green lights observed by Texas Tech professors and photographed by a student became a classic unsolved Project Blue Book case.
Nick Mariana filmed two bright rotating discs over Great Falls, Montana, producing one of the earliest credible pieces of UFO film evidence.
Paul and Evelyn Trent photographed a metallic disc over their Oregon farm, producing the most analyzed and authenticated UFO photos in history.
A 1949 Los Alamos conference transcript in which Manhattan Project physicists tried and failed to explain the 'green fireball' wave over the Southwest's nuclear laboratories. Released via PURSUE Release 04.
USAF pilot George Gorman engaged in a 27-minute aerial dogfight with a maneuvering light over Fargo that outperformed his P-51 Mustang.
Two Eastern Airlines pilots observed a cigar-shaped craft with glowing windows pass their DC-3 at close range, prompting Project Sign's ET conclusion.
Declassified file documenting 209 green-orb and disk sightings around the Sandia Base atomic-weapons complex, 1948-1950; released May 22, 2026 via PURSUE Release 02.
The US military initially announced recovery of a 'flying disc' near Roswell, NM before retracting the statement, creating the most famous UFO controversy in history.
Private pilot Kenneth Arnold's sighting of nine unusual objects near Mount Rainier launched the modern UFO era and coined the term 'flying saucers.'
Over 800 UFO sightings in just two weeks during the summer of 1947 created a nationwide phenomenon that launched government investigations and permanently changed American culture.
Over 2,000 reports of rocket-shaped objects over Scandinavia prompted a Swedish military investigation that concluded 80% were unexplained.
The US military fired over 1,400 anti-aircraft rounds at unidentified objects over LA weeks after Pearl Harbor, with a famous searchlight photo capturing the event.
During the 1897 airship wave, a craft allegedly crashed into a windmill in Aurora, TX, with reports of a non-human pilot buried in the local cemetery.