I know a lot of about one bird that was widely reported as a UFO.
When I was in the USAF, we all were shown a video, on what this bird was capable of, and after this video, and Officer got up and told us it was just a conventional aircraft, but "to tell people who saw it land, you don't know what they are talking about, there is no such aircraft as far as we know it. It was an experimental top secret aircraft, and if they wanted to believe it was a UFO, let them believe it, because that is the perfect cover story for that top secret aircraft." That was in 1971. Now how much more advanced are our top secret aircraft today ? ? ?