I don't believe in ghosts any more than I believe in gods, Santa Claus, the tooth fairy, or an honest politician.
As to aliens, I rather expect they exist, have existed, or will after we're gone. The fact that life exists at all is a decent argument for more, considering the ridiculous scales of time and space that constitute the universe as we know it. As realists will point out, however, our chances of encountering sapient life on a level where it can communicate across the stars or send things into space are dismally low for pretty much the same reasons. I dismiss claims of UFOs as ridiculous. Crossing light years is no mean feat at any speed, and you mean to tell me that aliens have done this in order to abduct cows or fat rural people? Spare me.