Quote Originally Posted by cliveh View Post
Zen in the Art of Archery by Eugen Herrigel.
I second that recommendation. A fascinating book in spite of its flaws, and it seems to be undeservedly forgotten.

It won't fill up a 15-hour flight, though. The best books I've found for that purpose are Thomas Pynchon's longer ones, but as far as I can think they're off-topic.