Travelers are prone to getting blood clots in their legs after long haul flights, a condition called deep vein thrombosis. If this has ever happened to you, it is important to inform your family doctor for advices and management plans.
To prevent this from happening, throughout the flight, it is crucial for you to
1) stand up and take a walk, back and forth the corridor several times,
2) stretch/exercise your calf muscles,
3) wear clot-preventing support stockings, and
4) keep up with fluid intake, especially water.