A number of pilots in the United States Navy reported seeing unidentified flying objects (UFOs) over American airspace between 2014 and 2015.

One of them, Lt. Ryan Graves, said he saw UFOs on an almost daily basis in the airspace off the Eastern seaboard between Florida and Virginia.

These UFOs would reach altitudes of up to 30,000ft and flew at hypersonic speeds without leaving any visible engine exhaust, Graves told The New York Times.

Graves said he reported what he witnessed to the Pentagon and Congress.

The Times story features video of two encounters Navy pilots allegedly had with UFOs.

The videos include visual radar and voice recordings by pilots who are amazed at what they see.

'What the [expletive] is that thing?' one pilot is heard saying as he is unable to positively identify an object in his radar

A number of pilots have reported seeing objects flying at altitudes of up to 30,000ft above the Eastern seaboard between 2014 and 2015

Pilots said that the flying objects were able to stop suddenly and turn quickly while reaching hypersonic speeds

‘These things would be out there all day,’ Graves said.

‘With the speeds we observed, 12 hours in the air is 11 hours longer than we’d expect.’

Graves said the most unusual thing about these UFOs was their ability to stop suddenly, turn on a dime, and immediately accelerate to hypersonic speeds.

‘Speed doesn’t kill you,’ Graves said. ‘Stopping does. Or acceleration.’

In 2014, a pilot operating a Super Hornet fighter jet reported that he nearly collided with a UFO.

The pilot recalled that something which resembled a ‘sphere encasing a cube’ flew in between two fighter jets that were flying around 100ft apart from each other.

Another pilot, Lt. Danny Accoin, said he noticed a flying object on his radar, missile system, and infrared camera, but he wasn’t able to see it in his helmet.

‘I knew I had it, I knew it was not a false hit,’ Accoin said.

‘[But] I could not pick it up visually.’

The pilots began to notice more activity after their radar systems were upgraded, but most thought they were false radar tracks.

The UFOs were spotted in areas that were designated for fighter jet training, which makes it unlikely that these were commercial drones or other objects that are classified.

But none of the pilots or the Pentagon would speculate as to what they believed the objects were.

'We’re here to do a job, with excellence, not make up myths,' said Lt. Accoin.

The pilots' claims come a week after a Department of Defense spokesperson reportedly confirmed the Pentagon's interest in UFO's, citing the agency's investigation of 'unidentified aerial phenomena.'

According to a report from the New York Post, a representative confirmed that the U.S. government studied and investigated the occurrence of mysterious and unexplained aircraft as a part of the Advanced Aerospace Threat Identification Program that was made public in 2017.

Media commentator and former British defense official Nick Pope told the Post that the specific choice of words marks a major step in the way that the government talks about unidentified aircraft.

'This new admission makes it clear that they really did study what the public would call ‘UFOs,’ he told the Post.

'It also shows the British influence, because UAP was the term we used in the Ministry of Defence to get away from the pop culture baggage that came with the term ‘UFO.'

The shift in terminology comes just weeks after the U.S. Navy unveiled new guidelines on collecting information about UFO sightings.

As reported by Politico, the guidelines are designed to make it easier for sailors to report UFO sightings amid fears that mysterious unidentified flying objects could actually be 'extremely advanced Russian aircraft.'

The Navy has reported an uptick in the number of 'highly advanced aircraft' encroaching on its air space.

Last week, the Pentagon admitted it had studied 'unidentified aerial phenomena'

In 2017, former Pentagon official Luis Elizondo made headlines when he detailed the existence of the UFO-focused Advanced Aerospace Threat Identification Program - a $22million government operation that studied UFOs

Among the sightings were reports from pilots of two U.S. Navy Super Hornet fighters who spotted a UFO on a training mission

'There have been a number of reports of unauthorized and/or unidentified aircraft entering various military-controlled ranges and designated air space in recent years,' a spokesperson for the Navy said to Politico in April.

Throughout the last several years, the U.S. Government has shown an increasing willingness to acknowledge its investigation and interest of UFO's.

In 2017, former Pentagon official Luis Elizondo made headlines when he detailed the existence of the UFO-focused Advanced Aerospace Threat Identification Program - a $22million government operation that studied UFOs.

The secretive program sought to identify UFO sightings through U.S. surveillance and eyewitness reports and then 'ascertain and determine if that information is a potential threat to national security.'

Among the sightings were reports from pilots of two U.S. Navy Super Hornet fighters who spotted a UFO on a training mission.

The pilots reportedly spotted a mysterious vehicle, around 40ft long, oval-shaped and whitish, hovering erratically above the ground.

The craft 'had no plumes, wings or rotors,' but traveled at a mile per second. When pilots approached the object, it easily outran the military jets.

Elizondo resigned from his post in 2017 in protest over what he has termed excessive secrecy and internal opposition to the project.

Although the Pentagon officially stopped funding the project in 2012, reports from the New York Times suggest the program is still operating.