So you must think that either he was lying, or an idiot who didn't understand what he was seeing, or that he was taken over by demonic spirits, because the other possibility, that these extra-terrestrial craft and creatures exist, you have taken off the table.
I would LOVE to take it off the table in my own mind, because I would MUCH prefer to believe that we'll never be threatened by them. However, ignorance is bliss, and I've read too much and heard anecdotes personally from too many folks I know well and trust, to indulge in the luxury of not "believing." What I want to believe and what IS, are two different things in this case. I would rather believe the way you do, but I cannot.