49. Free Miles For Pretty Quiet and Still Company
This one is a bit morbid but apparently not as uncommon as you might think. In an International Air Travel Association study, it was discovered that there were about 72 in-flight deaths a year on average.

To be clear, these are unrelated to the planes themselves and generally come from an older person reaching the end of their lifespan or having a medical emergency that can’t be taken care of quickly enough (though a plane will often check its manifest for a physician on board if needed).