D.S.
Michaels has some great little coloring crafts for 1.00. They are those little velvet ones and come with markers. I would go look at their crafts section. Stickers, small matchbox type cars, simple lightweight books. I like to take snacks that take a little more time to eat, but may not be messy. Like those little peanut butter crackers or small cookies, m&ms or smarties.
When I'm traveling I don't take anything I don't mind getting lost unless it is one special stuffed animal they like.
Oh and I don't pull out the toys, crafts or snacks until my children are bored of all the sights and sounds going on around them.