Air travel is the best/worst. You travel really far! Really fast! It beats the hell out of hauling cross country in a covered wagon. Still, planes today are cramped and uncomfortable, and can leave you feeling lethargic for days afterward.
Exercise is one of the best ways to combat jet lag and the muscle fatigue associated with flying. Some basic movements can prepare your body to fly and to recover from a flight. You can also make yourself feel better and more relaxed while you're in the air. Here's a primer.