I work at air canada and I am a groomer, I spend a lot of time in planes and I have never experienced something like this. I was in a plane alone, the last person had gone out for a break so I was left alone, it was late at night and I was tired, and I had this feeling that I was being watched so I kept on turning around to look but there was never anything there until I heard a faint noise, it was a kind of whisper and it was calling my name. It couldn't have been one of the groomers because I heard the last one leave and if someone were to come in, I would have heard the door. I thought I was imagining things so I just kept working, but I kept on hearing the whisper and it was getting louder and louder and that feeling of being watched never left me so I just ran out of the plane in terror.
The next day I told some of my friends about it (they were also groomers) and they said they had that same feeling on the same plane and that things were moving around when they weren't looking, it was really scary, but they got the plane blessed for safety reasons in case anything like that happened in the air. I will never forget that night.
But in one of the stories there was a plane that crashed, and killed people, some of the parts where still usable and went into other planes, and the pilot and some crew who had died went with the plane parts into the new one, after a lot of sightings they took the parts out and didn't use them again, so maybe the same thing happened