DVT is caused by being inactive. This results in a blood clot. The clot normally lodges itself deep in your leg or pelvis. The nasty bit about this, is that, the clot or part of it can travel north and make a new home in your lungs. This will make you very ill indeed (a pulmonary embolism) and at worst kill you.

There are precautions you can take to try and prevent this fate;

Regularly exercise your feet and legs by either walking around the aircraft cabin or if the seat belt sign is switched on do some leg exercises focusing on your feet and calves.

Get yourself some elastic socks/stockings. They may not be the height of fashion but who cares when could go along way to help prevent a clot.

Cut down on alcohol. If possible avoid it all together and drink as much water as you possibly can to keep your body well hydrated.

Some general practitioners suggest that you can take a low dosage of aspirin to thin the blood prior to take off. Your lifestyle however, will perhaps, ultimately determine how much at risk you are. The usuals prevail; smoking, being overweight, excessive drinking etc.

Should you be at all concerned about DVT visit your doctor prior to your next flight.