Last week my super hip and cool Silicon Valley brother-in-law gave us a gift for the plane called My Busy Kit. On the last day of our vacation, Aunt and Uncle California gave each kid a Busy Kit bag customized for his/her age. Henry's had crayons, a pad for drawing, Klix, little men that connect, small car, a quiet noisemaker, shards of broken glass, etc. The bag (with zipper closure) itself was also entertaining. He loved taking the toys out and putting them back in. The toys were all appropriate for quiet play (shards of broken glass weren't actually included), and new, which is always intriguing.
Busy Kits are meant to entertain kids during travel, church, etc. Ideally you can purchase them online or at the airport at the newsstand. Then you keep them hidden until the exact moment you need to entertain your child.
AWESOME idea for busy parents who don't have time to pack their own bag 'o entertainment.