A pair of amateur plane trackers captured strange footage earlier this month of an unidentified airborne craft that appeared to hover above Air Force One as President Joe Biden visited Los Angeles.

Unsurprisingly, speculation that it was extraterrestrial in origin began almost immediately.

"A few viewers are saying we saw a UFO," Peter Solorzano, who runs the YouTube channel L.A. Flights with his brother Joshua Solorzano, said with a laugh during the Dec. 10 livestream.

The plane spotters had set up that day to film footage at Los Angeles International Airport (LAX) as two F-35 fighter jets patrolled the skies for the Commander-in-Chief. While they were elated to film the jets being refueled mid-air by a KC-10 tanker aircraft, they didn't expect to capture anything as unusual as the white sphere that came into view.

What's more, the brothers didn't just capture footage of it once, but three times.

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'I'm kind of scared looking at this'

The object first appeared to zoom across the screen at 10:18 a.m. local time as it traveled in the opposite direction above Air Force One.

Joshua recognized it right away.

"You saw that? We got something flying in the way," Joshua said. "I'm not too sure what it was."

Watch the video here (skip to 1:30 for the first sighting of the object:

Minutes later, it appeared again, prompting Joshua to comment that "it was moving around weird."

By the time the object appeared on camera for the third and final time at 11:08 a.m., Joshua was starting to become unnerved.

"I'm kind of scared of looking at this," he said. "I'm not sure what that is, could it be a balloon? I'm thinking balloon."

His brother, though, wasn't buying it.

"Are you just saying that to keep certain authorities away?" Peter asked.

The Solorzano brothers did not immediately respond Friday to USA TODAY's request for comment.

Skeptics dismiss UFO sighting as balloon

But some skeptics are already dismissing the sighting as having a mundane explanation.

Author Mick West, a well-known a UFO debunker, reviewed the footage for DailyMail.com and concluded it was most likely a balloon. As for the apparent motion in the video, West said it's likely an illusion caused by the balloon being closer to the camera than the fast-moving plane in the background.

"It looks like a balloon and moves like a balloon," West told the DailyMail.

The Pentagon's relatively new office to investigate UFOs, which the government refers to as Unidentified Anomalous Phenomena (UAP,) has identified more than 500 military encounters with the crafts since 2004.

While some of those reports defy an easy explanation, the Pentagon's e All-domain Anomaly Resolution Office (AARO) has said many have been determined to be natural occurrences such as unpiloted aircraft or weather balloons.

NASA is similarly insistent that no conclusive evidence has yet been found to determine that any reports of UAP are extraterrestrial in origin. However, the space agency recently hired a director of UAP research and released a report stating its intention to continue studying the phenomena that poses a potential threat to U.S. airspace.

Eric Lagatta covers breaking and trending news for USA TODAY. Reach him at [email protected]