When I Fly, it's for fun, and not for work most of the time. I try to keep expenses down by bringing enough snacks to last both the flight and a VDB, if luck should have it.

In my travel bag of food it the following;
Crackers and cheese, empty bottle for water (http://mysigg.com/), if I'm flying from home I bring a sandwich. When flying to home, a bag of dried fruit works well.
If I'm driving myself to the airport, and dropping off a rental car then a quick run through the Drive through for a burger.