If you sit in the same place for a long time on a plane or a bus, this can lead to a lack of exercise, which can promote the formation of dangerous blood clots. A thrombosis occurs when blood flow is blocked in the veins.
If you have a window seat on the plane, you should still get up regularly, especially on longer flights, and take a few steps up and down the aisle. Travelers should also wear thronbosis stockings.