I like short stories for planes.

Recently I read All the Names They Used for God (don't let the title put you off) and it was phenomenal. Ted Chiang is also good for short stories, even if some of them are tedious.

Other than short stories, I also like short novels in general for planes. It's nice to be able to actually finish something. Maybe short classics like The Picture of Dorian Gray or Tarzan.

Or just read whatever you're reading while on your trip.