The Anomalous Aerial Vehicle (AAV) is a term used within US military and intelligence circles to describe unidentified airborne objects encountered during operational activity, most prominently a series of encounters involving the Nimitz Carrier Strike Group (CSG-11) (CSG-11) off the coast of California and Baja California, Mexico, in November 2004. The term was later adopted by the Advanced Aerospace Threat Identification Program (AATIP), a Department of Defense programme established to collect and analyse information involving such objects.1
During the incident on 2004-11-14, personnel aboard USS Princeton (CG-59), a cruiser equipped with AN/SPY-1 radar, detected the AAV on three separate occasions over the course of the week while operating off the western coast of the United States and Mexico.2 The AN/SPY-1 radar was set for a mode intended for the air intercept of conventional aircraft, and consequently never obtained an accurate track of the object, repeatedly dropping the contacts as clutter.3 On the day of the intercept, USS Princeton took control of a flight of two F/A-18F aircraft of Strike Fighter Squadron 41 (VFA-41), vectoring them toward the AAV and bringing them to visual contact at a range of approximately 1.6 kilometres from the object.4 David Fravor flew as pilot of the lead aircraft, callsign FastEagle 01,5 with Alex Dietrich piloting the second aircraft, FastEagle 02.6
Pilots who observed the object described it as an elongated egg or “Tic Tac” shape with a discernible midline horizontal axis,7 solid white and smooth with no visible edges.8 It measured approximately 14 metres in length.9 Chad Underwood, who flew a separate F/A-18F sortie later that day at the request of Fravor’s flight crew,10 gave a matching description: solid white, smooth, with no edges, uniformly coloured, and with no nacelles, pylons, or wings.11 The F/A-18Fs’ onboard radar was unable to obtain a lock on the object, though it could be tracked with forward-looking infrared (FLIR) while the object was stationary or moving slowly.12 Underwood attempted multiple times to achieve a Single Target Track radar lock on the object without success,13 and reported no jamming cues or other normal electronic-attack indications on his radar during the attempt.14
Fravor’s first indication of the object was a visual disturbance on the water surface beneath it, after which he gained visual on the object itself.15 He described the disturbance as localised directly under the object rather than resembling a trail or wake, with frothy waves and foam that gave the impression the water was boiling.16 Fravor remarked that the object was “holding like a Harrier”,17 a reference to the AV-8B Harrier’s ability to hover via thrust vectoring. Beginning a descent with the intention of making a close pass to visually identify the object,18 Fravor assessed that it appeared to recognise his aircraft’s approach, realigning its axis to point toward him.19 As his flight completed the manoeuvre, the object ascended rapidly and pulled a lift vector on and aft of the F/A-18Fs at what Fravor assessed as supersonic speed,20 after which the flight rejoined and returned to USS Nimitz (CVN-68).10 During Underwood’s later sortie, the object began moving out of his FLIR field of view; he made no attempt to slew the sensor and lost situational awareness of it.21 Copies of the FLIR footage were made, with one set delivered to the ship’s intelligence section.22
Investigators also examined whether the object could have operated undersea. USS Louisville (SSN-724) was operating in the vicinity of USS Nimitz as part of CSG-11 during the detection and intercept period,23 and a former submarine officer who served aboard her at the time said there were no unidentified sonar contacts during the period of the sightings.24 On this basis, the incident report assessed it highly unlikely that the AAV operated below the ocean surface, while noting it remained possible the object had demonstrated a capability to be cloaked or invisible to the human eye, given pilot reports of water disturbance with no visible craft.25
Following the intercept, Fravor reported to the Carrier Intelligence Center (CVIC) and discussed the encounter with the Carrier Air Wing Intelligence Officer,26 who said that he and his colleagues did not initially take the report seriously but had no reason to question it, given that it came from an experienced and well-respected squadron commander.27 The Intelligence Officer went on to describe a high level of ridicule directed at the aircrew in the weeks that followed.28 The encounter was documented in an email-based mission report and forwarded via secure channels to Third Fleet Intelligence (Senior Intelligence Officer (N2)),29 where it was read and acknowledged but not forwarded further up the chain of command.3 Carrier Strike Group 11 (CSG-11) was commanded at the time by Rear Admiral D. C. Curtis, later a Vice Admiral commanding Naval Surface Forces;4 the group’s Director of Operations (N3) said that beyond the mission report, no other official statement was made regarding the AAV, and that the strike group at no point considered it a threat to the battle group.30 Peter Daly assumed command of CSG-11 in January 2005, after the intercept, with no knowledge of or involvement in the incident.1
The AAV terminology resurfaced years later in connection with AATIP, the Department of Defense programme tasked with collecting and analysing information on such objects.1 Luis Elizondo, who described the programme’s mission in these terms, stated that AAVs studied under AATIP had been observed reaching between 600 and 700 G-forces31 and flying at speeds of approximately 21,000 kilometres per hour,32 and that the objects showed no obvious signs of propulsion, wings, or control surfaces.33