Kids get cranky and frustrated when they are bored! So when my kids where younger and we would be traveling either by car, plane, boat or all of the above, I would always have a kids size backpack and they would help pack the bag for the trip and they would carry it. Of course I would also sneak a few new things into their bags as a surprise. Both of my kids are great travelers now that they are older and they know now to pack things themselves to keep their minds and hands occupied.