Bottom Line
When the All-domain Anomaly Resolution Office (AARO) has enough data to close a UAP case, the answer is usually a balloon. Drones, birds, satellites, and aircraft account for most of the rest. The largest group of reports, however, is never resolved at all, because the data needed to identify the object does not exist. Only a small number of cases each year show characteristics AARO considers worth deeper study.
The Numbers
AARO's fiscal 2024 annual report covered May 1, 2023, to June 1, 2024. In that period the office received 757 new reports, bringing its total to 1,652. It resolved 118 cases and queued 174 more for closure. Of the cases it closed, 70 percent were attributed to balloons, 16 percent to drones, 8 percent to birds, 4 percent to satellites, and 2 percent to aircraft.
The same report placed 444 new cases in an archive because they "lacked sufficient data for further analysis," and identified 21 that merited further analysis based on reported anomalous characteristics or behaviors.
The fiscal 2025 report, released in July 2026 and covering June 2, 2024, to May 30, 2025, followed the same pattern at a smaller scale. AARO received 319 reports, resolved 114 of them, and resolved another 256 older cases, all to ordinary explanations. It flagged 9 reports for additional analysis.
Both reports state the office found no evidence of extraterrestrial beings, activity, or technology.
| Explanation | Share of closed cases |
|---|---|
| Balloons | 70% |
| Unmanned aerial systems (drones) | 16% |
| Birds | 8% |
| Satellites | 4% |
| Aircraft | 2% |
1. Balloons
Balloons dominate for a simple reason: there are a lot of them, they are hard to judge at a distance, and they move with the wind rather than under their own power. Weather balloons, research balloons, party balloons, and sky lanterns can all appear to hover, drift sideways at steady speed, or catch sunlight after dark on the ground.
AARO's analysis of the 2018 "Mt. Etna object" shows how convincing a balloon can look. A U.S. drone filming an eruption over the Mediterranean captured an object that seemed to fly straight through the volcanic plume with no effect. After 3D modeling and pixel-level analysis, AARO assessed with moderate confidence that the object was a balloon drifting with the wind roughly 170 kilometers from the volcano. It only appeared to cross the plume from the camera's viewpoint.
Clue: an object moving in a straight line at a steady speed in the same direction as the wind.
2. Drones
Consumer and commercial drones are now the second-largest category. At night, a drone is often just a cluster of lights, and its ability to hover, climb, and change direction abruptly can look like "impossible" maneuvering to an observer who assumes it is much larger and farther away. AARO's fiscal 2025 report also noted 50 drone notifications near U.S. nuclear infrastructure, none of which it classified as UAP.
Clue: red and green navigation lights, a buzzing sound at close range, or erratic movement at low altitude.
3. Birds
Birds are a common culprit in infrared and daytime video. A single bird close to a camera can look like a large, fast object far away, and flocks can reflect light unpredictably. Without a range measurement, nothing in the frame tells the viewer which it is.
Clue: irregular, flapping, or fluttering motion, or several objects moving loosely together.
4. Satellites and Starlink
Satellites have become a fast-growing source of reports, especially from pilots. AARO has repeatedly noted reports it could trace to SpaceX's Starlink constellation, including a commercial pilot's report of "white flashing lights" that matched a Starlink launch from Florida.
Freshly launched Starlink satellites travel in a tight line, often called a "train," that looks unlike anything most people have seen. Sunlight glinting off satellite panels can also create sudden flares that appear and vanish. In the fiscal 2025 report, AARO said the space-domain reports it examined, 42 of them from FAA-relayed pilot reports, were consistent with reflected sunlight from satellites, using three-dimensional modeling.
Independent researchers have reached the same conclusion in specific cases. A 2024 paper by Douglas Buettner and colleagues reconstructed an August 10, 2022, incident in which five pilots on two commercial flights over the Pacific reported a UAP. Using orbital data for a Starlink batch launched that day and the flights' positions, they showed the pilots were seeing the new satellites in unusual lighting.
Clue: evenly spaced lights moving in a line, or a light that brightens and fades over seconds shortly after sunset or before sunrise.
5. Aircraft and Parallax
Aircraft make up a small share of closed cases, but parallax, the illusion that fools observers into misjudging aircraft, also explains some of the most famous military videos.
The Navy's "Go Fast" video appears to show a small object skimming the ocean at high speed. AARO's analysis found the object was at roughly 13,000 feet, not near the water, moving at about 39 knots (45 mph) in winds of about 60 knots. The fast-moving Navy jet, flying into the wind, created the impression of speed. AARO assessed with high confidence that the object showed no anomalous flight characteristics.
Parallax also played a part in AARO's review of an April 26, 2013, infrared video from a U.S. Customs and Border Protection aircraft over Puerto Rico's Rafael Hernández Airport, which appeared to show an object racing along, splitting in two, and plunging into the sea. AARO found two separate objects drifting at wind speed, about 3.6 meters per second, that never entered the water. The "splitting" came from the changing camera angle, and the apparent disappearance into the ocean came from thermal crossover, the point where the objects and the water were the same temperature on the infrared sensor.
Clue: any video taken from a moving aircraft, where the camera's motion can make slow objects look fast.
The Biggest Category: Not Enough Data
More reports end up in AARO's archive than in any explanation category. In fiscal 2024, 444 new cases were archived for insufficient data, far more than were resolved. These are not mysteries in any meaningful sense; they are reports without the time, location, direction, range, or sensor information needed to test an explanation. AARO says archived cases can be reopened if new data surfaces.
NASA's independent UAP study team made the same point in its 2023 final report: "the data needed to explain these anomalous sightings often do not exist." Eyewitness reports, it noted, "can be interesting and compelling, but aren't reproducible and usually lack the information needed to make any definitive conclusions."
What Remains Unexplained
Ordinary explanations do not cover everything. AARO flagged 21 cases in fiscal 2024 and 9 in fiscal 2025 for further analysis because of reported anomalous characteristics. Some well-known historical cases, such as the 2004 Nimitz encounter, remain unresolved largely because the original sensor data is not publicly available.
The honest reading of the data is that most sightings have ordinary causes, most of the rest cannot be analyzed, and a small remainder deserves careful study. None of those findings supports assuming a sighting is extraordinary, and none rules out that a rare case might be.
Checklist: Before You Report a Sighting
- Write down the basics right away: time, your location, compass direction, how high above the horizon, and how long you watched.
- Check the sky trackers: a satellite pass predictor such as Heavens-Above, recent rocket launch schedules, and a live flight tracker such as Flightradar24.
- Note the wind: an object drifting steadily downwind is very likely a balloon or lantern.
- Film with a reference point: keep a rooftop, tree, or horizon in the frame, and avoid zooming while recording, so motion can be judged.
- Save the original file: screenshots and re-uploads lose the time and location metadata that investigators need.
- Report it with context: use the UAP Radar sighting form and include everything above.
Key Points
- In fiscal 2024, 70% of AARO's closed cases were balloons and 16% were drones.
- More cases are archived for insufficient data than are resolved.
- Starlink satellites and satellite flares are a growing source of pilot reports.
- Parallax explained AARO's findings on the Go Fast and Puerto Rico videos.
- AARO flagged 21 cases (FY2024) and 9 cases (FY2025) for further analysis.