▶ Watch Video: U.S. report finds no evidence UFOs were alien spacecraft

After decades of dismissing U.F.O. sightings popularized in American culture, a U.S. government task force assigned to investigate what it calls “unidentified aerial phenomena,” or UAPs, has found no evidence that objects came from outer space or a foreign adversary. 

However, while there’s no evidence the objects are extraterrestrial, senior government officials said Friday that nearly all of the incidents investigated remain unexplained.

“Of the 144 reports that we are dealing with here, we have no clear indications that there’s any non-terrestrial explanation for them,” a senior government official said, nixing the possibility of exotic sightings. “But again, we will go wherever the data takes us on this.”

U.S. government officials who briefed reporters on Friday said there is no doubt that identified UAPs were physical objects, tamping down speculation that sightings could be optical illusions caused by atmospheric conditions or sensor malfunctions. 

“From a safety of flight issue, we absolutely do believe that what we are seeing are not simply sensor artifacts. These are things that physically exist,” a senior government official said. “They are physical objects.” But officials stressed that objects detailed in the 144 reports represent a “variety” of phenomena.  

In 80 of the 144 investigated incidents, the task force detected objects using multiple sensors, leading officials to determine UAPs posed a hazard to flights. Over the years, the task force determined there have been 11 near misses.

Congress in December asked the Pentagon’s Unidentified Aerial Phenomena Task Force (UAPTF), along with the Office of the Director of National Intelligence (ODNI) and other intelligence agencies, to submit a report on what is known about UAPs; relevant committees received a classified version of the report on Friday, before the unclassified version was publicly released. Read the report here:

Officials pored over 144 incidents between 2004 and 2021, relying heavily on observations made by military aviators. 

Without evidence that UAPs are operated by an adversary like China or Russia, government officials say there is no reason to believe that a foreign power has made a technological breakthrough in recent years.

“A small portion of the data set has propulsion we cannot explain,” a senior government official said. “That doesn’t necessarily mean that there is an adversary that is introducing a technological surprise here.”

The report found that 18 objects investigated possess propulsion systems that cannot be explained, due in part to insufficient data and reporting. 

The report categorized the incidents into five explanatory categories: 

  • Airborne clutter, like birds, balloons and plastic bags

  • Natural atmospheric phenomena, like ice crystal formations or thermal fluctuations

  • Industry developmental programs

  • Foreign adversary systems, including possible technologies deployed by Russia or China 

  • “Other,” which, the officials said, was a “catch-all” section where a lack of data or scientific knowledge meant the incident was uncategorizable.

Officials said they were limited in their analysis by the nature of the data underlying the incidents, which came chiefly in the form of verbal reports that were only occasionally supported by video or photographic evidence. The task force has since begun work on a new mechanism through which they hoped to standardize data collection on UAPs and apply scientific and engineering approaches to their explanation, they said.

“Ultimately, we have to increase the volume as well as the quality of the data we have,” one official said. 

The officials told reporters a “majority” of the information included in the classified report was presented in the unclassified version. They said neither agency would be releasing any supplementary evidence, including photos or video, of the phenomena the report had assessed.

Limited information about the UAPs has trickled out over the last few months. The Defense Department task force confirmed in April that the scope of its work includes objects described as a “sphere,” “acorn,” “pyramid” and “metallic blimp” by military personnel.

In May, CBS News’ “60 Minutes” spoke with naval aviators David Fravor and Alex Dietrich, who had never before talked publicly about their encounter in Southern California in 2004 that was visible on their radar and on video when they were flying in the Nimitz carrier strike group. They observed an object that looked like a Tic Tac moving over whitewater in an otherwise calm blue sea. 

The two said that they saw the object, about the size of their F/A-18F, but with no markings or wings and also without exhaust plumes, mimicking the movements of their own plane.

“Oh there’s, there’s definitely something that … I don’t know who’s building it, who’s got the technology, who’s got the brains. But there’s — there’s something out there that was better than our airplane,” Fravor told “60 Minutes” correspondent Bill Whitaker.