In 2017, Luis Elizondo, a former Pentagon official, had shared a video showing an encounter between the US Navy and a UFO in 2004. The official also said we are not alone and there is evidence of alien life.
"My personal belief is that there is very compelling evidence that we may not be alone," Elizondo told CNN in 2017.
The video showed a mysterious object that defied physics and displayed characteristics that were "not currently in the US inventory nor in any foreign inventory that we are aware of."
This claim was supported by David Fravor, a retired commander and US Navy pilot, who gave a detailed description of the UFO and called it a "40-foot-long Tic Tac" flying at incredible speed.
However, sceptics have debunked the UFO theory and said the object in the video could be a misidentified plane in the far distance, Express.co.uk reported.
Mick West, the administrator of debunking website Metabunk.org, wrote in a forum: "I'm thinking the black shape around the object is some kind of IR flare/glare. We know that the shape of a very bright IR source, like the engine of a plane, can be much bigger than the object itself.
"Of note is the 'cold' glow around the hot sources, indicating that's just a camera thing. If people try to describe this as some kind of 'aura' or 'field' then they obviously have not done their homework.
"If it's actually a distant airliner with a 200 foot wingspan, and the 'saucer' shape is actually flare, then the effective length on the long visual axis there would be more like 500 feet. Hence 120 miles away."
West also explained why the object made strange movements in the video. According to him, this could be the plane moving in the direction opposite to that of the camera.
"The sensor heading indicator is very interesting because it goes from 54°L to 6°R. The orientation of the shape flips as it goes over from left to right. The plane is turning left, the camera is turning right. The change in angle of the camera appears fairly constant.
"After more analysis I think it's probably a distant aircraft, as when the camera moves, the position of the object moves in sync with the far clouds, which tends to indicate it's part of the environment."
However, several social media users and UFO buffs have said they are not convinced with West's theory.
"The video in question comes from a gun cam. Fighter pilots are extremely well trained people. To assume that they are incapable of using their equipment and are not competent to distinguish a plane from something unusual is really stretching it," one Reddit user said.