Darkening Humour just make watching movies on airplanes illegal. I'd want to include watching films on hand-held devices for much the same reasons. Poor visuals, too many distractions... just not good.
However, some movies might improve, or at least not lose any of it's stellar qualities, on an airplane. Sure, it's easy to put Airport, Goldeneye and Air Force One on the list, because that context might heighten the drama, but that's too easy. What movies would you say, "Yeah, this is a film that is perfect for the airplane watching experience?"
-Arachnophobia, because the spiders are small enough that I don't get scared any more.
-The Room, which already looks like a TV show and I can turn my head and take off the headphones to take a nap and I won't miss anything.