The day before Thanksgiving may be the busiest travel day, but you don't have to put away your healthy foods.
If you are driving, put some fruit and vegetables in a cooler, so you can snack during your trip.
Also drink plenty of water, it will help curb your appetite.
Before you board that airplane, try to eat a piece of fruit before you go through security, and then have a high fiber bar or granola bar before you board.
That should hold you over until you reach your destination.