I read on a blog (shoot, wish I remembered where I read that) a mom put together surprise bags of little trinkets, little activities or snacks that she new here kids would enjoy and they gave one out every hour. It help the time go by quickly and it gave the child anticipation of when and what the next bag was.
Otherwise... my son probably would be anything electronic and alphabet related. And if that didn't work... food and more food... things he wouldn't normally get at home.
Good luck and safe travels!!
