A still image from video released by the Department of Defense shows a an unknown object as seen from a Navy F/A-18F fighter jet.

What we know from decades of UFO government investigations

Mysterious flying objects. Claims of crashed alien spacecrafts. The U.S. has spent decades inquiring into the unknown—here's what they've learned.

This image released by the U.S. Department of Defense shows a 2004 encounter between two Navy fighter jets and an unknown object near San Diego. But are UFO sightings like this one a sign of extraterrestrial life, spies from a rival nation—or just weird weather? 
Photograph by DEPARTMENT OF DEFENSE/The New York Times/Redux

There’s something strange going on in the sky, but what?

Unidentified flying objects are much in the news lately after a whistleblower claimed that the United States had discovered the remains of a crashed alien spacecraft

The Pentagon denied the report, but the U.S. Congress remained interested—and, in June, the House Oversight Committee announced it will hold a hearing on UFOS—or as the U.S. government calls them, “Unidentified Aerial Phenomena” (UAPs).  “In addition to recent claims by a whistleblower,” a committee spokesperson said, “reports continue to surface regarding unidentified anomalous phenomena.”

Such reports have been surfacing for decades. The modern era of UFO sightings and investigations started after World War II with a sudden surge of unexplained reports.

(How the Pentagon learned to start worrying and investigate UFOs.)

U.S. officials didn’t necessarily dream of meeting extraterrestrials in their investigations: As the Cold War with the Soviet Union got underway, American leaders worried that UFOs represented a threat from a rival nation. Aliens never invaded, although new sightings happen all the time—as do investigations into those reports. 

How to keep track of it all? Here’s a timeline of our ongoing fascination with UFOs.

(For our subscribers: Something in our galaxy is flashing every 20 minutes—but what?)

1947-1969: Project Blue Book

Over the course of two decades, the U.S. Air Force cataloged 12,618 sightings of UFOs  as part of what is now known as Project Blue Book. These include lights, objects, and unexplained radar readings reported by military and civilian pilots, weather observers, astronomers and other sources.

The project came to an end in 1969 after a study by the University of Colorado concluded there was no evidence that UFOs came from other worlds, and that most sightings could be explained by natural phenomena, or even hoaxes. “Our general conclusion is that nothing has come from the study of UFOs in the past 21 years that has added to scientific knowledge,” said the study leader, Edward U. Condon. Further investigation, he said, “cannot be justified.” 

Still, rumors and sightings persisted—sometimes to the annoyance of the original investigators. The Air Force announced in a 1985 fact sheet that “there are not now nor ever have been, any extraterrestrial visitors or equipment on Wright-Patterson Air Force Base,” where the investigation was headquartered.

1995: A U.S. senator takes interest

The Condon report didn’t put an end to interest in UFOs. So-called “UFOlogists” spent the next few decades filing open records requests with federal agencies to uncover what was known about the sightings.

(The legend of Area 51—and why it still fascinates us.)

In 1995, businessman Robert Bigelow convened a small group in Las Vegas to discuss the possibility of alien life: He called the group the National Institute for Discovery Science. Participants included two former astronauts, Ed Mitchell and Harrison Schmitt, and one sitting U.S. senator: Harry Reid, Democrat of Nevada.  

“A lot of people said it would ruin my career,” Reid later said. That didn’t quite happen: Reid would eventually become a key figure in driving the U.S. government’s investigation of UFOs.

2004: An encounter off San Diego

In November 2004, two Navy pilots on a training mission were ordered to intercept a mysterious craft. They saw—and captured on video—an unusual oval-shaped craft, about 40 feet long, hovering over the Pacific Ocean about a hundred miles off San Diego. It streaked away before the pilots could get near. “I have no idea what I saw,” said one of the pilots, Cmdr. David Fravor, at the time. “It had no plumes, wings or rotors and outran our F-18s.” 

2007: A new Pentagon investigation

With backing from Reid—now the U.S. Senate’s majority leader—the Pentagon launched the Advanced Aerospace Threat Identification Program to investigate the latest round of sightings.

“What was considered science fiction is now science fact,” the agency said in briefing papers. The program was run by a military intelligence official,  Luis Elizondo, and worked hand-in-hand with an aerospace research company run by Bigelow. 

2014: A near-collision on the East Coast

In a series of incidents during this time, Navy pilots reported—and made video recordings—of a series of encounters with unidentified craft near Florida and Virginia that could reach high altitudes and hypersonic speeds. One pilot reported a near-collision in 2014. Another later told 60 Minutes that the craft were hard to explain. “You have rotation, you have high altitudes. You have propulsion, right? I don't know. I don't know what it is, frankly.” 

One possibility? Surveillance craft from another country. 

2017: Going public

These incidents and investigations mostly went unreported to the broader public—until December 2017, when the New York Times reported the existence of the Pentagon’s Advanced Aerospace Threat Identification Program. Although Pentagon officials said the program had ended in 2012, Elizondo told the paper he continued its work informally with cooperation from the Navy and CIA until his resignation in the fall of 2017. 

That sparked a new wave of interest in UFOs among the public, the media, and even scientists. 

2020: A scientific call to action

In July 2020, Ravi Kopparapu and Jacob Haqq-Misra—a NASA scientist and astrobiologist, respectively—wrote in Scientific American that it was time to revisit the conclusions of the Condon report. “Perhaps some, or even most, UAP events are simply classified military aircraft, or strange weather formations, or other misidentified mundane phenomena,” they wrote. “However, there are still a number of truly puzzling cases that might be worth investigating.” 

(Here's where earthbound travelers can search for extraterrestrial life.)

In August 2020, the Pentagon announced the Unidentified Aerial Phenomena Task Force to “improve its understanding of, and gain insight into, the nature and origins” of the unidentified objects.

2021: DNI report

In April 2021, the Navy confirmed video of unidentified objects “buzzing” U.S. warships near California. The incident would be added to the list of sightings under investigation.

In June, the Office of the Director of National Intelligence (DNI) released its “preliminary assessment” of UFO sightings from 2004 to 2021. The report suggested that the UFOs—now known as UAPs—could fall into five likely categories: airborne clutter, natural atmospheric phenomena, public and private aerospace developmental programs, foreign adversary systems, “and a catchall ‘other’ bin.” More funding and reporting was needed, the report said. 

2022: NASA jumps in to investigate

In April 2022, the Pentagon announced the formation of the All-domain Anomaly Resolution Office to investigate objects “that might pose a threat to national security.” 

The following June, NASA announced it was setting up an independent study program to cover the issue from a scientific perspective. “We will be identifying what data—from civilians, government, nonprofits, companies—exists, what else we should try to collect, and how to best analyze it,” said David Spergel, the study team leader. 

And 2022 also brought another acronym change: “Unidentified Aerial Phenomena” are now officially called “Unidentified Anomalous Phenomena.” 

2023: The truth is still out there

Whatever is happening up above, it still hasn’t entirely been explained. The DNI released a follow-up report in June 2023, identifying an additional 510 sightings—of which 171 remained unexplained. In those cases, unidentified craft often “appear to have demonstrated unusual flight characteristics or performance capabilities,” the report said.

Most explosively, a former intelligence official named David Grusch came forward in June with a whistleblower report alleging the U.S. government was in possession of “intact and partially intact vehicles” from UFO crash sites. The craft, he said, were of “non-human” origin. But he also said he had never personally seen the objects, inviting skepticism from outside experts. 

“In the long history of claims of extraterrestrial visitors, it is this level of specificity that always seems to be missing,” said Boston University’s Joshua Semeter, a professor of electrical and computer engineering and a member of the NASA team examining these reports, told BU Today. The evidence may be wanting, but the questions—and the sightings, and the investigations—continue. 

Read This Next

The legend of Area 51—and why it still fascinates us
In the hunt for alien life, this planet just became a top suspect
Barnacles could help solve the mystery of MH370

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet