I picked up a copy of No Country for Old Men by Cormac McCarthy. The book is an old time western set against the backdrop of modern Texas, with drug running and paid killings that usually happen in the background brought to the fore.
The book is a well-written thriller with a lean prose that Hemmingway would have been proud of. Because of this it was very easy to read and very easy to pick back up and read some more. It is also more than a thriller, providing a view of modern society through the eyes of its protagonists.
The book also has a bleak morality more akin to Sergio Leon's spaghetti westerns were good doesn't always win out and the good have more than their own fair share of faults and demons.
If you need a book for an airport, pick this one up and run with it.