Eating healthy at an airport does not have to be a disaster.
Do some research- take a look at what your restaurant options will be and look up the nutrition info ahead of time. Give yourself some options so that you don't scramble last minute and end up with a 1,000 calorie breakfast.
Skip the unnecessary extras- you can easily skim off calories by watching what is added to your food (like cheese or mayo on a sandwich), and what is on the side (french fries, chips or cookies). Dressings can add a few hundred calories to salads if you aren't careful. Some quick reading can save your butt, literally.
Eat often. Waiting until you are starved can direct you towards unhealthy choices, and foods that you would not normally eat. Pack some snacks to help avoid a hunger frenzy. I always travel with protein bars, fruits and veggies to keep me on my normal routine.
Get protein when you can. Avoid the purely carbohydrate based choices like bagel & cream cheese, pizza, pasta, muffins and smoothies.
Drink plenty of water. Being dehydrated may give you false cravings for salt or sugar. A bottle of water may save you from that cookie with 12 teaspoons of sugar.
Sleep. Getting adequate rest helps to make smarter choices. Sleep deprivation can steer you toward more processed carbs and sugar.
Get a game plan. Have an idea of about what time you will be eating so that when boredom strikes you don't just jump in line and order aimlessly. Don't just try to wing it, this can lead to many more snacks than if you were in your normal daily routine.