It depends on what you like to read...
Funny books are always good:
- Any of David Sedaris' books.. he writes very funny essays, like Naked or Me Talk Pretty One Day
- Hokkaido Highway Blues by Will Ferguson is also quite funny. A guy, on a bet said he would hitchhike from the one end of japan to the other and this is just a book about his experiences
Long Books for Long Flights:
- I love 100 years of solitude by Garbriel Garcia Marquez.... its a magical realism book, so it's not for everyone, but things like the whole town gets insomnia or the town's founder is tied to a tree for years, etc.
- If you like fantasy books, George R.R. Martin writes a huge huge series, like 800 pages per book about these different families fighting to be king. I believe the first is a clash of kings.
Finally if you want to learn something:
- All the president's men by Bob Woodward and Carl Bernstein... just to find out about Watergate and Woodward writes quite well
- Red China Blues by Jan Wong writes about her experience as a Canadian who is one of the first undergraduates allowed to study at Beijing University during the height of the cultural revolution.. she does write about Tiananmen Square and her point of view during that time..
Also i do like Harry Potter, it seems like an excellent plane book.
Okay now that i've written an essay, i hope this helped and i don't see too long-winded.