As the title says really! What can I buy him that is suitable? All his toys will be in our container so I need to get him something small enough for hand lugguage but not noisy so it keeps people awake!
make sure you have an endless supply of snacks that take a while to eat. Don't worry about "proper" meals on this occasion - lots of little bits will keep him occupied. raisins in a box, little sandwiches, etc etc
I once did a 12 hr flight alone with my 18m DS - a bag of plastic farm animals were the hit toy of that particular flight. He put them in and out of the bag a zillion times