Captain Dune,
My first reaction is to think of the lower kind of journalism ( so no offence to Jackonicko ) - as a UK photographer on the military side of BAe, I saw some odd things from other countries ( no, not other planets ) , but which common sense dictates any country would grab given the chance.
I had the sense not to photograph them, as I could tell what was going on and the officer accompanying me became very twitchy when he realised I knew what I'd seen.
Much more relevant, John Farley mentions seeing / knowing the A12 /SR71 from the early 1960's...
In the early - mid 1980's a BAe team at a famous USAF base were suddenly told to turn their backs, and not look on pain of being shot, when a mystery aircraft came in.
A, I doubt very much the Americans would have fired,
B, I would guess this was the F-117 before it became public.
C, Could have been a flying saucer, but I think option B rather more likely - ( have no doubt that UFO's exist, every doubt as to what they are, but I'm pretty sure a big-eared cigar smoking F-18 driver couldn't just jump in and fly one ).