Good for 'white' noise while doing computer stuff
This movie benefits from its relatively simple premise... it's essentially a haunted house story set in a commercial airliner. The build-up is effectively creepy and relies on imagination rather than special effects to generate a sense of unease.
About halfway in though the story and the overall acting take a turn for the worse. Suddenly various small screen actors are screaming and screeching with various degrees of histrionics. By comparison William Shatner is the most restrained actor in the cast at this point!
For a 70s vintage movie, it holds up moderately well. The simple plot and relaxed pace (by today's standards) allow you to play this in the background -- maybe on a separate monitor -- while you are doing more meaningful stuff on your 'puter.