I've always been sceptical about this kind of thing but a while ago I read that two air force pilots flying over the English channel encountered some kind of silver craft. When they tried to get near it it disappeared at a speed far in excess of anything any plane on earth can do. So this wasn't some whacked-out guy making something up or somebody trying to get tourists to come to their backwater town, this was people who are eminently trustable and believable. There are endless billions of planets in our galaxy and endless billions of galaxies other than ours so it stands to reason that some other motherfuckers are out there somewhere.