Mellon made the suggestion during a May 18 interview with journalist Chris Cuomo.
"It's a hypothesis that could explain the fact," he said. "People need to be open to that. We're spending billions looking for extraterrestrial civilizations, we've got spacecraft that have already left the solar system. It's possible somebody found us before we found them."
Mellon was joined by retired Navy Chief Master-of-Arms Sean Cahil, who was at the scene when Navy pilots witnessed a Tic Tac-shaped UFO in 2004. The Department of Defense (DOD) released a video of the UFO along with two other clips in April last year. Commenting on the footage, Cahil said that the aircraft on display appeared to be several years ahead of U.S. technology.
"The technology that we witnessed with the Tic Tac was something we would not have been able to defend our forces against at the time," the ex-pilot said. He added that the craft's exceptional feats of flight "indicate a technology that outstrips our arsenal by at least 100 to 1,000 years at the moment."(Related: Advanced, non-human UFO technology repeatedly observed, documented and filmed by U.S. Navy pilots.)
Multiple pilots witnessed the mysterious object as it flew over the Pacific Ocean near Mexico in November of 2004. According to Cahil, the aircraft had zero control surfaces and lacked any visible means of propulsion despite traveling at hypersonic speeds. This led to speculation that the craft was a UFO, becoming a key piece of evidence for those who believe extraterrestrial intelligence exists.
When asked to provide a possible explanation for the military's UFO sightings, Cahil answered that the objects could be a large spectrum of things, ranging from enemy aircraft to technologies that are not made on Earth. He hesitated to speculate on the exact source but said he believes UFOs are not man-made.
Mellon appeared to agree with Cahil on the matter, noting that there is no scientific basis to doubt the possibility of alien technology.
Mellon urged the government to pay attention to UFOs because highly advanced vehicles had repeatedly trespassed restricted American airspace over the past several years.
"They're very capable, in some cases more capable of anything in our own inventory. This has been going on for years. The truth is just emerging," he told Cuomo.
He opined that the country is vulnerable to what's out there given that intrusions had been going on for too long without the government taking action. While there were no hostilities so far, sightings increased recently and they are "increasingly bold," he said.
Just recently, a number of unidentified aircraft swarmed Navy warships off the coast of California and a similar incident happened around strategic missile defenses in Guam, he pointed out. Taking note of the tension between the U.S. and its adversaries, Mellon said that the nation's top officials need to take UFOs seriously. (Related: Leaked Pentagon footage shows what appears to be pyramid-shaped UFOs swarming Navy warship.)
Sen. Marco Rubio made a similar call during a May 16 interview on CBS News' "60 Minutes." He noted that anything intruding into U.S. airspace should be considered a threat, but the stigma surrounding UFOs precluded serious examination of America's intruders.
"There's a stigma on Capitol Hill," he told show correspondent Bill Whitaker. "I mean, some of my colleagues are very interested in this topic and some kinda, you know, giggle when you bring it up. But I don't think we can allow the stigma to keep us from having an answer to a very fundamental question."
Navy Lieutenant Commander Alex Dietrich, a witness of the Tic Tac UFO, said that the stigma also kept witnesses quiet.
"Over beers we've said, 'Hey man, if I saw this solo, I don't know that I would have come back and said anything,''' Dietrich told Whitaker on the same show. "Because it sounds so crazy when I say it."
Retired Navy Commander Dave Fravor, another witness of the 2004 sighting who gave chase to the aircraft, concurred with Dietrich: "I've had some people tell me, 'When you say that, you can sound crazy.'" He told Whitaker that he's not a "UFO guy" but confirmed that the sightings were real.
These interviews came as the Pentagon and other intel agencies are expected to present Congress a report on UFOs next month. Former Director of National Intelligence John Ratcliffe teased last March that the report would detail sightings that are "difficult to explain."
Read the latest news related to UFOs at UFOs.news.