I have no problems believing that machines can leave ghosts. Especially those that have been exposed to the pyschic energies of hightened emotions, or long exposure to lower levels. A sort of hand-off field of psychic energies, leaving an embedded pattern in reality in the shape of the machine.

And I've seen a couple myself, including a ghost plane of WWII vintage flying into a decommisioned airfield nearby. One that was semi-transparent in the intermittent moonlight... [and yeah, that was damned spooky!]