The Gameboy is a good idea. My son had one for traveling when he was that age. I do still bring a little soft side cooler for snacks and such when we travel. I brought sliced cheese, salami and crackers this past summer and some dip.
These days he would be happiest with a laptop loaded with his favorite games for a long flight like that. Now that I mention it, so would I! With a DVD, you could even bring your own movies.
Don't forget headphones and pillow.
Edit: I was too tired to think about it last night when I posted
[This message has been edited by tazi (edited 10-29-2002).]