I think it is quite likely that most of the UFOs are piloted by time travelers, not aliens.  For some reason, ufo enthusiasts have decided that we are the center of the universe and that aliens from all across the galaxy visit us on a regular basis.   My question is this:  Out of all of the uncountable billions of stars in the universe, what makes them think that the aliens would be able to find us at all?  I’m not saying it’s not possible, I’m just not convinced.  On the other hand, however, time travelers would know exactly where to find us and how to get whatever it is they need from us.