Amid a recent increase in speculation about unidentified flying objects, President Donald Trump has admitted to at least one meeting about the topic.

But there's been no proof that alien spacecraft are flying around earth, and Trump himself said he was doubtful that's the case.

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In an interview with ABC News set to air on Sunday, President Donald Trump admitted he has had "one very brief meeting" to discuss reports of unidentified flying objects made by US Navy pilots.

Despite the reports, Trump said he himself does not put much stock in the idea of alien visitors.

"I think it's probably — I want them to think whatever they think," Trump told George Stephanopoulos. "They do say, and I've seen, and I've read, and I've heard, and I did have one very brief meeting on it. But people are saying they're seeing UFOs."

"Do I believe it? Not particular," the president added.

Trump was asked if he thought he would know if there was extraterrestrial life. He said he thought "my great pilots would know. Our great pilots would know."

"They see things a little bit different from the past," Trump added. "So we're going to see. We're watching, and you'll be the first to know."

' These things would be out there all day'

Interest in possible unidentified flying objects — a term for anything in the air that can't be explained — has flared in recent weeks, after the Navy said it was drafting new guidelines for personnel to report encounters with them.

"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," the Navy told Politico, which first reported the change.

An apparently unidentified object detected on a Navy plane’s infrared camera. US Department of Defense/Navy Times

The Navy added that it investigates each incident out of safety and security concerns and that it was "updating and formalizing the process" by which those incidents are reported and analyzed.

A recent New York Times report also detailed several such encounters between summer 2014 and spring 2015, when Navy pilots flying over the East Coast reported seeing objects traveling at high speeds and high altitudes but without visible engine or infrared exhaust.

"These things would be out there all day," said Lt. Ryan Graves, an F/A-18 Super Hornet pilot who reported his sightings to the Pentagon and Congress.

"Keeping an aircraft in the air requires a significant amount of energy. With the speeds we observed, 12 hours in the air is 11 hours longer than we'd expect," Graves, who has been in the Navy for 10 years, told The Times.

The reports and policy changes don't indicate that the military is coming around to the idea that extraterrestrial craft are visiting earth, according to Iain Boyd, a professor of aerospace engineering at the University of Michigan and scientific adviser to the Air Force.

"Humans' misinterpretation of observations of natural phenomena are as old as time," Boyd wrote in May, adding that he thought the Pentagon was likely looking to improve its identification process to avoid confusion as more sophisticated systems, like autonomous aircraft, enter service.

"Until humans understand UFOs better, we won't be able to teach computers about them," Boyd wrote.

But the recent developments are likely seen as vindication by two high-profile people: Harry Reid, a Nevada Democrat and former Senate majority leader who pushed to fund a shadowy Defense Department program that investigated UFO sightings, and Tom DeLonge, a former Blink-182 guitarist who founded an organization to prove aliens exist.