https://www.history.com/news/chris-mellon-ufo-investigations
"Could these crafts be…ours?
The first question all of us have asked when we've seen the information is: Could this possibly be one of our own programs, a highly classified U.S. test program?
I served in a capacity in which it was my job to conduct oversight of our black programs, and never saw anything of this kind on the books. Moreover, I was once actually specifically asked to determine whether we had a capability along these lines, in response to a query from the chairman of the Senate Appropriations Committee, Senator Bobby Byrd.
I ran that all the way up the flagpole with the Air Force and others, and believe me, everyone respected Senator Byrd. No one was going to lie to him and risk his wrath. And the answer was, “Absolutely not. We don’t have a super-secret black triangle that can go at hypersonic speeds and all that sort of thing.”
Secondly, a technology like this is so radical, it can't just appear out of nowhere. There have to be facilities, there has to have been research and development, a prototype. We don't see any evidence of that anywhere.
Thirdly, these aircraft are being observed operating in and around carrier battle groups that are armed with air-to-air missiles and so forth. We never, to my knowledge, put at risk those personnel—or test personnel—by flying them in an uncoordinated manner against carrier battle groups. That's just not how we operate."