Wear loose, non-constricting clothing that allow you to move around easily. Shoes should be easily removed and replaced by soft slippers which allow the feet to be exercised easily.
While waiting at the airport instead of sitting in the passenger area, walk around the airport terminal as long as possible.
When on the plane, stretch your feet out as much as possible. Rotate the ankles by making circular motions, clockwise and counter-clock wise about every twenty minutes. Point and flex the toes repeatedly for a few minutes. Push down on floor with the ball of the foot to constrict the calf muscles.
If possible, take a short walk around the cabinet which encourages the pooled fluids to be pumped back around the body.
Avoid soft drinks that may have sodium or salty goods such as salty peanuts or pretzels. The best thing to drink is just water which will keep you hydrated in the usually very dry air in the plane.
