Also remember that the snacks cannot be in a gel-type form. So no pudding cups, no containers of peanut butter (but you make a PB&J sandwich ahead of time and bring it). No tubs of cream cheese, but you can take bagels with cream cheese already spread on them. You can bring a soft sided cooler with frozen veggies to keep the food cold. The cooler may count as a personal item, but I'm not sure. I know that when you buy food in the airport and bring it in a bag onto the plane, that bag does not count toward your luggage allowance.