UFO-type sightings happen more often near military airspace

a c-17 aircraft at night
A C-17 aircraft in Afghanistan in 2018.

It is the Department of Defense’s responsibility to secure the skies above the United States from potential threats. Following the transit across the US in February of a large balloon originating in China, the Air Force scrambled jets to shoot down new objects seen with more sensitive radar apertures. This led to the shoot-downs of several objects. Finding unknown objects in the sky is hard work, which is why the Pentagon commissioned think tank RAND to map public reports of Unidentified Aerial Phenomena across the United States.

RAND’s report was completed in May 2023, sent to the Department of Defense for review, and published on July 25. One day later, on July 26, former Department of Defense employee David Grusch testified before a House Oversight and Accountability subcommittee, specifically offering statements on Unidentified Aerial Phenomena, or UAPs. The term is largely a modern rebranding of UFOs, after the latter abbreviation became shorthand for objects potentially connected with extraterrestrial life. The hearing attracted far-reaching headlines, as well as disputes regarding Grusch’s claims from news media and the Pentagon alike.

The question of what people spot and keep spotting in the skies above the US is real. The RAND report, with access to great swathes of data, offers a good starting point for understanding this topic. When it comes to modern observations of Unidentified Aerial Phenomena, the RAND study’s most concrete finding is that unknown aircraft are most commonly reported near Military Operations Areas (MOAs), or swathes of the sky designated for military practice and maneuvering. These areas are not necessarily near air bases.


The history of UFO sightings and Project Blue Book

For decades, air traffic over the United States was largely limited to commercial and military vehicles, with onboard human pilots. Other types of flying machines, like balloons or uncrewed target drones, were used within specific areas, and would sometimes show up in public reports of unusual phenomena. (The sensor-carrying balloon that crashed outside of Roswell, New Mexico in June 1947 is likely the most famous of these.)

Following a flying saucer panic in the US in 1947, the Air Force collected public reports of Unidentified Flying Objects through Project Blue Book. An analysis of Blue Book sightings, conducted by the University of Colorado in 1969, found that at least 90 percent of sightings could be explained as naturally occurring phenomena, like Venus seen at dawn. Of the remaining 10 percent that could not be publicly explained, documents declassified in 1992 revealed that fully half of those sightings were Americans reporting the flight paths of US spy planes, like the U-2. These were flying objects known to the government, but not known to the public.

Area 51, the Air Force base that is almost synonymous in popular culture with alien research, was started as a place to test the U-2 spy plane. It is still in use to this day for flights of experimental craft, and the military secrecy around the bases’ contents and operations lend it an outsized air of mystery.

What the RAND report found about UAPs today

To understand where and why Americans are reporting unusual sightings in the sky, RAND researchers Marek N. Posard, Ashley Gromis, and Mary Lee started with the National UFO Reporting Center database. Established in 1998, the NUFORC is a nongovernmental entity that allows people to report sightings, and through a moderation process filters out obvious hoaxes. The researchers used that data to answer two questions at the heart of the report: where in the US are people likely to report such sightings, and what factors predict where people are more or less likely to report UAP sightings?

The sightings were matched to US census-designated places, then compared to places of interest, like military bases, MOAs, airports, and weather stations. The data set is big, with researchers finding 101,151 reported UAP sightings in 12,783 census-designated places from 1998 to 2022.

“The most consistent—and statistically significant—finding from our models was for reports of UAP sightings in areas within 30 km of MOAs,” write the authors. “According to the FAA, ‘MOAs are established to contain nonhazardous, military flight activities,’ including air combat maneuvers, air intercepts, and low-altitude tactics. Given this association, we suspect that some of the self-reports of UAP sightings to NUFORC are authorized aircraft flying within MOAs.”

A good example of an MOA is the Desert MOA, situated north of Las Vegas, Nevada. It’s near Nellis Air Force Base, but planes are also likely to fly from Nellis to Carson MOA, which is far from any air bases.


Notably, reported sightings of UAPs went down when people were within about 19 miles (30 km) of an Air Force or Navy base, and they also went down further than 37 miles (60 km) away. Being within 37 miles of an airport reduced the rate of sightings. While weather stations did not change the frequency of sightings, weather did, as for “each additional 1 percent of cloudy days, the expected rate of all UAP sightings increased by 1.6 percent.”

Taken altogether, the research suggests that people are more likely to not report unusual sightings of aircraft when they are in an area where they expect aircraft to be, like by an Air Force base.

“One possible explanation for this pattern of findings is that people located in more–densely populated areas, near airports and near weather stations, are more aware of the types of objects that fly overhead and nearby and are therefore less apt to report aerial phenomena,” write the researchers.

Identifying the unknown

New aircraft, like cheap high-altitude balloons or abundant hobbyist drones, are already changing how people see and understand the sky. Air Force sensors are geared towards identifying larger crewed aircraft. One policy choice posed by the RAND study is if there is value in the military turning to public reports of unusual aircraft.

The authors offer three suggestions.

“First, we recommend that government authorities (e.g., local and state government officials, the FAA, and DoD) conduct outreach with civilians located near MOAs,” they write. This would help people near skies used by the military, but far from airbases, understand what exactly it is they are observing. Being near an airbase makes the presence of aircraft intuitive, but training areas exist largely on maps until they are abruptly in use, with no ground-based indicators highlighting what is happening. “Second, we recommend that government authorities conduct additional outreach to notify nearby civilians when there is airspace activity near a MOA,” the authors continue.

The authors’ third recommendation is a new evaluation to inform the design of a detailed and robust system for public reporting of UAP sightings. A new reporting tool could improve precision in location, in tools used to record sightings, and ideally would be designed to filter out hoaxes or known objects.

“In conclusion,” they write, “the U.S. government has a large swath of airspace to monitor at a time when there is greater access than ever to small, technologically advanced, and inexpensive aerial objects. If officials believe that public reporting could be a valuable tool to help manage U.S. airspace, it will be important to ensure that members of the public report actual threats. Greater transparency in how sightings are collected, investigated, and used may also help mitigate the conspiracy theories that have long surrounded aerial phenomena.”

It has been so long since the military first collected data about unusual sightings that the UFO term has transcended its role as a military acronym. Instead of relying on a non-governmental tool to capture reports from the public, a new government-created tool for civilians may offer a way to understand the skies better, but it is unlikely that reporting alone will be enough to dispel conspiracy theories.

Correction on August 9: This article has been updated to remove a reference in the first paragraph to a hobbyist balloon that had potentially been linked to a shoot-down of an object on February 11, 2023.