I am entirely sure that, although intelligent life may appear elsewhere in the universe, aliens & alien spacecraft, as we imagine them, do not exist. I assure you that any crafts being seen are quite terrestrial in origin. Most people that claim to see UFOs are either delusional, a liar seeking attention mostly, or just plain have a fucking $ching-ching$ agenda.
The same goes for ghosts, but that opens up a big can of shit debating that one because if a delusional person sees a ghost, then it
is more-or-less real
to them. Most "ghosts" are seen when going to sleep or when awakened from sleep & thus, people see & hear things that an independent observer right next to them would not notice.
http://www.sonicyouth.com/gossip/sho...ht=unconscious