Doctors suggest unsalted snacks, protein-rich bars, or mini rice cakes with peanut butter. When coupled with a bottle of water, which you'll most likely have to buy at the airport due to today's security rules, these combos will help fill you up without weighing you down.
If you'd rather have a mini meal than snacks, choose wisely when selecting a venue. For example, if you're craving Mexican food, choose grilled veggies and meats, rather than fried foods. If you want pizza, go for a loaded slice of veggie pizza with a piece of fruit or raw veggies instead of a cookie or chips.
When selecting pre-made sandwiches, look for the ones made with whole wheat bread, light on the condiments and loaded with lean meats. And if you must have coffee and a muffin, go for low fat options.
Happy traveling and enjoy your flight on a happy stomach.