Actually, I think it is entirely possible that they (or some of them) are time travellers from our own future or even inter-dimensional travellers. In which case, they would still be "alien", in a sense, but in a different sense. If we found a way to go back in time and visit Vikings or cavemen I think they'd find us quite alien in appearance...and we'd probably be in considerable danger of being attacked by them.

As for square AFO's...well, maybe there are some, but a square does not strike me as a very harmonious design shape for a vehicle, given the various possibilities. :-) Still, why not? It would make a good freight carrier (like a cub van).

We'll have definitive answers...or at least a move in that general direction...when our governments decide to openly inform the public...or when MJ12 decides to openly inform the civilian government. :-)

I know someone who knew Pierre Trudeau (once Prime Minister of Canada) personally, and that person one day asked Trudeau, in private, what he knew about the "flying saucers". He looked right back at them with a poker face and said, "Don't ask me." And he simply would not discuss the matter.

There is a level of security over this whole thing that is just incredible. If there had been nothing to it, Trudeau would have been free to say, "Oh, there's no such thing. Don't worry about it." He didn't say that, because he didn't want to lie to a friend.

And yes, they could be top secret vehicles built by our own military...but I really doubt that, given what I've seen. It seems very unlikely to me.