When taking a long flight, if it is difficult to move around the cabin then curl or press your toes down often throughout your trip.

Long periods of immobility can cause blood clotting (deep vein thrombosis or DVT) in the legs. Therefore, it is important to move around the cabin as this squeezes the blood vessels and prevents the formation of blood clots. This also keeps your blood circulation up. However, if it is difficult to move around then curl or press your toes down often throughout your trip. Crossing your legs should definitely be avoided.