What Is a UAP? Definition, History & Official Investigations

UAP: Full Form, Meaning, and Official Definition

UAP full form: Unidentified Aerial Phenomena (sometimes Unidentified Anomalous Phenomena in the broadest congressional definition). The U.S. Office of the Director of National Intelligence (ODNI) officially defined UAP in its June 2021 Preliminary Assessment Report as 'airborne objects not immediately identifiable.' In 2022, Congress broadened the term in the National Defense Authorization Act (NDAA) to include 'transmedium' objects operating in space, air, and underwater. UAP meaning extends beyond simple misidentifications — it encompasses objects demonstrating flight characteristics that exceed known human aerospace capabilities: instantaneous acceleration, hypersonic speeds without sonic boom, low observability, and transmedium travel. The shift from 'UFO' to 'UAP' was deliberate: it removes the cultural stigma and extraterrestrial connotation of 'flying saucer,' replacing it with a neutral, scientifically descriptive label that encourages rigorous analysis.

UAP vs UFO: Why the Language Changed

The term UFO (Unidentified Flying Object) was coined by the U.S. Air Force in the late 1940s during Project Sign, the first official government UAP investigation. For 70 years it dominated both official and public language. However, UFO became culturally loaded — synonymous with alien spacecraft, science fiction, and conspiracy theories. This stigma discouraged military pilots and scientists from reporting sightings for fear of career consequences. The Pentagon's deliberate adoption of 'UAP' in 2021 served a dual purpose: it neutralized the stigma, making reporting socially acceptable within the armed forces, and it broadened the category to include underwater and space-transiting objects. Today 'UAP' and 'UFO' are used interchangeably in casual speech, but in official government, congressional, and scientific contexts, UAP is the correct and current term. NASA adopted the same terminology in its 2023 UAP Independent Study Report.

Five Observable Characteristics of UAP

Military sensors and pilots have consistently reported five observable characteristics that define the most credible UAP encounters. These were formally catalogued by the Advanced Aerospace Threat Identification Program (AATIP) and presented to Congress: (1) Anti-gravity lift — objects operating without visible lift mechanisms such as wings, rotors, or exhaust; (2) Sudden acceleration — instantaneous velocity changes that would crush a human pilot under conventional g-forces, sometimes exceeding 400–700 g; (3) Hypersonic velocity without sonic boom — observed at speeds exceeding Mach 5 with no detectable acoustic signature; (4) Low observability — radar cross-section characteristics inconsistent with the object's apparent size; (5) Trans-medium travel — seamless transition between air and water environments. The 2004 USS Nimitz Tic-Tac UAP exhibited all five characteristics simultaneously during a multi-day encounter with the USS Princeton's SPY-1 radar system and F/A-18 Super Hornets from the carrier air wing.

U.S. Government UAP Investigations: AATIP, AAWSAP, and AARO

The U.S. government has conducted several classified and unclassified UAP programs. The Advanced Aerospace Weapons Systems Application Program (AAWSAP, 2008–2012) was the first major modern program, funded with $22 million under the Senate's request from Sen. Harry Reid. Contracted to Bigelow Aerospace Advanced Space Studies (BAASS), it investigated UAP incidents and produced classified reports. Its successor, the Advanced Aerospace Threat Identification Program (AATIP, 2012–2017), was led by intelligence officer Luis Elizondo and focused on military UAP encounters. AATIP produced 38 classified research papers on advanced aerospace technologies. In 2022, Congress established the All-domain Anomaly Resolution Office (AARO) as the permanent, independent body responsible for detecting, identifying, and attributing UAP across all domains. AARO reports directly to the Deputy Secretary of Defense and the Director of National Intelligence, and is required to submit annual unclassified reports to Congress. As of 2026, AARO's historical record contains over 1,650 documented UAP reports.

The Most Credible Documented UAP Cases

Several UAP encounters stand out for the quality of multi-sensor evidence and official documentation. The 2004 USS Nimitz Carrier Strike Group incident — also known as the Tic-Tac encounter — involved simultaneous radar tracking by the USS Princeton's SPY-1 system and visual confirmation by Commander David Fravor and Lt. Commander Jim Slaight in their F/A-18s. The declassified FLIR1 video was officially released by the Pentagon in April 2020. The 2014–2015 USS Theodore Roosevelt incidents produced the Gimbal and GoFast videos — both declassified — showing objects with no visible propulsion system performing maneuvers inconsistent with known aircraft. For historical cases, the 1947 Roswell incident, the 1980 Rendlesham Forest incident (UK), and the 1989–1991 Belgian UFO Wave involving F-16 interceptions remain among the most thoroughly documented pre-AARO cases. France's official body, GEIPAN (formerly GEPAN/SEPRA under CNES), has investigated UAP since 1977 and maintains one of the world's most rigorous scientific archives, including the 1981 Trans-en-Provence landing case.

Congress and UAP: The Legislative Timeline

Congressional interest in UAP accelerated dramatically after 2017, when The New York Times published an exposé on AATIP. Key legislative milestones include: the FY2020 NDAA establishing a UAP Task Force (UAPTF); the June 2021 ODNI Preliminary Assessment acknowledging 144 UAP incidents; the FY2022 NDAA creating AARO and requiring annual unclassified reports; the UAP Disclosure Act of 2023 (Schumer-Rounds amendment), modeled on the JFK Records Act, mandating declassification of UAP records and establishing a UAP Records Review Board. Whistleblower protections were expanded through the Intelligence Authorization Act. Former AATIP director Luis Elizondo testified before the Senate Armed Services Committee, and whistleblower David Grusch's 2023 testimony before the House Oversight Committee — alleging the U.S. government possesses non-human craft — triggered multiple congressional investigations into alleged UAP retrieval programs.

NASA and the Scientific Study of UAP

NASA commissioned its first independent UAP study in 2022, with a 16-member panel including astrophysicists, data scientists, and a former astronaut reporting in September 2023. The NASA UAP Independent Study Report concluded that UAP pose a genuine scientific and aviation safety problem, that existing data is insufficient to rule out extraordinary explanations, and recommended that NASA develop a systematic data collection strategy using its existing sensor infrastructure. NASA appointed its first Director of UAP Research, Mark McInerney, in 2024. The Galileo Project at Harvard University, led by Professor Avi Loeb, conducts the first systematic scientific search for UAP evidence using a network of ground-based all-sky sensors combining infrared, visual, and radio detection. Several peer-reviewed papers on UAP have been published in journals including Aerospace, Entropy, and the Journal of the Washington Academy of Sciences.

How to Report a UAP Sighting in 2026

In the United States, civilian UAP reports can be submitted to AARO's official public reporting mechanism at aaro.mil/report-a-uap, launched in 2023 as mandated by Congress. Military personnel must report through official DoD channels. The FAA collects reports from pilots through the Aviation Safety Hotline (800-255-1111) and ASRS reporting system. In France, GEIPAN (geipan.fr) accepts civilian reports, which are processed by CNES scientists. In the UK, UAP reports previously went to the Ministry of Defence UAP desk, which closed in 2009; current reports can go through the Civil Aviation Authority. For researchers and investigators, the SCU (Scientific Coalition for UAP Studies) and NARCAP (National Aviation Reporting Center on Anomalous Phenomena) maintain independent scientific databases. Quality reports include GPS coordinates, timestamps, compass bearing, photo/video evidence, and corroborating witnesses.

FAQ

What does UAP stand for?

UAP stands for Unidentified Aerial Phenomena (or Unidentified Anomalous Phenomena in some congressional definitions). It is the official term used by the U.S. Department of Defense, Congress, NASA, and government agencies since 2021 to describe airborne or transmedium objects that cannot be identified as conventional aircraft, drones, weather balloons, or known technology.

What is the difference between a UFO and a UAP?

UFO (Unidentified Flying Object) and UAP (Unidentified Aerial Phenomena) describe the same category of unexplained objects but carry different connotations. UFO became culturally stigmatized through association with extraterrestrial spacecraft and science fiction. The U.S. Pentagon adopted UAP in 2021 to remove this stigma, encourage military reporting, and broaden the category to include underwater and space-transiting objects. In official U.S. government and NASA communications, UAP is the correct current term.

Has the U.S. government officially confirmed UAP exist?

Yes. The June 2021 ODNI Preliminary Assessment officially acknowledged 144 UAP incidents documented between 2004 and 2021, confirming they represent a real physical phenomenon that cannot be explained as U.S. experimental technology. The Pentagon has declassified three UAP videos (FLIR1, Gimbal, GoFast) filmed by U.S. Navy pilots. AARO's ongoing reporting program has logged over 1,650 cases as of 2026, including a significant subset that remain unexplained after analysis.

What is AARO and what does it do?

AARO stands for All-domain Anomaly Resolution Office. Established by Congress in the FY2022 National Defense Authorization Act, AARO is the permanent U.S. government office responsible for detecting, identifying, and attributing UAP across air, space, and underwater domains. It reports to the Deputy Secretary of Defense and the Director of National Intelligence, and must publish annual unclassified reports to Congress. AARO also manages the official public UAP reporting portal at aaro.mil.

What are the five observable characteristics of UAP?

The five observable characteristics formally documented by AATIP are: (1) anti-gravity lift without visible propulsion; (2) sudden and extreme acceleration (exceeding hundreds of g-forces); (3) hypersonic velocity without a sonic boom; (4) low radar observability inconsistent with physical size; and (5) trans-medium travel — seamless movement between air and water. Not all reported UAP exhibit all five characteristics, but the most credible military cases — such as the 2004 USS Nimitz Tic-Tac encounter — reportedly displayed all five simultaneously.

What is AATIP, and who ran it?

AATIP stands for Advanced Aerospace Threat Identification Program. It was a classified Pentagon program that ran from approximately 2012 to 2017 with funding of around $22 million annually, focusing on military UAP encounters. It was preceded by AAWSAP (Advanced Aerospace Weapons Systems Application Program, 2008–2012). AATIP was led by intelligence officer Luis Elizondo, who resigned in 2017 citing insufficient resources and skepticism from leadership, and later testified before Congress about the seriousness of UAP as a national security and scientific issue.

Can UAP be extraterrestrial in origin?

AARO has not confirmed any UAP as extraterrestrial in origin. Its 2023 preliminary report stated it found no verifiable evidence that any UAP represents extraterrestrial technology. However, AARO has also not definitively ruled out this hypothesis for a subset of cases that remain unexplained. Harvard's Galileo Project explicitly considers the extraterrestrial hypothesis as one of several scientific possibilities alongside classified adversarial technology, natural atmospheric phenomena, and sensor artifacts.

How many UAP reports does the U.S. government have?

As of AARO's most recent public reporting (2025–2026), the U.S. government has documented over 1,650 UAP cases. The original 2021 ODNI report covered 144 incidents from 2004 to 2021. Reports have increased significantly since the establishment of AARO's public reporting portal and the removal of stigma around military reporting. A significant percentage of new reports come from military pilots, naval vessel crew, and intelligence community personnel.

UAP — Unidentified Aerial Phenomena — have evolved from a Cold War stigma to one of the most pressing questions in national security and science. With Congress mandating disclosure, NASA conducting formal studies, AARO processing thousands of reports, and whistleblowers testifying under oath, the question is no longer whether UAP are real, but what they are, who operates them, and what they mean for aviation safety, national security, and our understanding of physics.