During long flights I strongly recommend the following exercises to become more comfortable during flying and to avoid the dangerous adverse effects of DVT or Deep Vein Thrombosis
Ankle Circles: lift your foot off the floor and draw a circle in the air with your toes pointed, altering direction. Continue for 30 seconds. Repeat with your other foot.
Foot Pumps: While keeping your heels on the floor, point your feet up as high as possible toward your head. Put both feet back flat on the floor. While keeping the balls of your feet on the floor, lift both heels high. Continue for 30 seconds.
Knee Lifts: While seated, march slowly in place by contracting each thigh muscle. Continue for 30 seconds.
Knee to Chest: hold your left knee and pull up toward your chest. Hold for 10 to 15 seconds. Slowly return to floor. Alternate legs for 10 minutes.
These exercises should not be performed if they cause pain or discomfort or if they are not recommended by your doctor.