There was an Eastern Airlines plane that crashed years ago and undamaged parts were salvaged and used in other planes after that. On planes that had those parts, there were ‘ghosts’ seen. I worked with a pilot who was on a plane that had a sighting and there was a part that the deceased pilot pointed out that needed attention. Not sure if he saw the actual sighting or another crew member but the pilot who told me about it was a stand up, no nonsense guy and I absolutely believed him.
There is more here about the plane crash and subsequent sightings:
https://en.wikipedia.org/wiki/Eastern_Air_Lines_Flight_401
There was a book written about this. “The ghosts of Flight 401. Believe there was a movie made.too. I was fascinated about this story.