U.S. Navy pilots reported seeing unidentified flying objects during training exercises on the East Coast in 2014 and 2015, according to The New York Times.
Several of the pilots spoke with The Times and said they would often see the objects traveling at hypersonic speeds, making sharp turns and sudden stops at sea level and as high as 30,000 feet. They also reported that the objects did not have any visible engines or infrared exhaust plumes.
Lt. Ryan Graves, who has been in the Navy for 10 years, spoke to The Times about some of the incidents he experienced and said that a few were videotaped, including one on a plane's camera in 2015.
In 2014, Graves said he and several other pilots began noticing the objects after their outdated radar was upgraded to a more advanced system. Once the updates happened, the radar began picking up the objects, but at first the pilots didn't pay much attention.
Graves said the objects continued showing up at heights of 30,000 feet, 20,000 feet and even at sea level. But he nor any of the pilots could actually see the objects without their radar.
In one instance, Graves said he interacted with one of the objects by flying 1,000 feet below it, according to his radar. He said when he looked up he couldn't see anything.
Another pilot said a training missile on his jet locked onto the object during another incident, but he couldn't see it with the naked eye. During this time, Graves and the other pilots assumed that maybe it was a secret drone program.
It wasn't until later that year that the pilots started seeing the objects, in one instance describing it as a circle inside of a cube.
At one point, one of those objects nearly crashed with another pilot as he flew over the Atlantic near Virginia Beach. The incident scared the pilot so much that a safety report was filed, according to The Times. That is when the pilots realized it might not be a secret drone program.
Graves and other pilots are featured in a six-part History Channel series called "Unidentified: Inside America's U.F.O. Investigation."
In The Times interview, the pilots did not want to speculate on what they saw.
Earlier this month, the Pentagon admitted that it still investigates reports of UFOs, or "unidentified aerial phenomena."
A Department of Defense spokesman told the New York Post that a secret government program called the Advanced Aerospace Threat Identification Program researched UFOs. It was shut down in 2012, but the DOD still investigates reports, including those from the Navy pilots.