The outline of the object changes from the shape of an aircraft into a Y-shaped figure.
The YouTuber claimed the object caught on camera could be a "plasma-based life form".
UF-WOW
"I've got this incredible sighting on film by a passenger on board an airline of what appears to be a shape-shifting object," he said.
"The plane's altitude is anywhere between 10,000 and 30,000 feet and this object is filmed over seven minutes above the altitude of the plane and it seems to be moving alongside with the plane.
"People are going to call this a UFO, well technically it is, but I'm leaning more towards this being a biological entity or a plasma-based life form living in our upper atmosphere."
The footage was shared on a UFO Reddit page where some people believed that the object was just a large water droplet outside of the window.
"I think it could be a camera zoomed in on a large water droplet on the outside of the window," the UFO-enthusiast wrote.
"Especially at the end, it looks like water under a microscope."
Another suggested that it could be a refraction pattern - which is when light waves change speed when passing the boundaries between such densities as air and glass.
"Especially toward the end, that looks very much like refraction patterns. Google 'refractograph' to see what some of those can look like," they wrote.
Meanwhile, the mystery of UFOs could finally be solved as the pioneering ‘Galileo Project’ launches a massive new hunt for aliens.
Space boffins urge "we must dare" to hunt for signs of s as "humans can no longer ignore the possible existence of Extraterrestrial Technological Civilizations".
The ambitious Galileo Project involves the creation of a global network of telescopes, cameras and computers to investigate unidentified flying objects.