Does an aspirin a day keep the Deep Vein Thrombosis away?

From The Boston Globe (Should I take an aspirin before a plane flight to avoid getting blood clots?)

No, according to new guidelines issued in June by the American College of Chest Physicians, though if you already take aspirin for general cardiovascular health, you should continue to do so while you travel.In everyday life, aspirin helps prevent clots in arteries by keeping platelets, the major element in plaque, from building up in ones arteries.But the type of clots triggered during long plane flights are different. They start in deep leg veins, says Dr. Michael Jaff, medical director of the vascular center at Massachusetts General Hospital.Deep vein clots are composed predominantly of fibrin, which aspirin does not affect.

With the economy down fewer people will be taking these long flights anyway. But the article does provide a number of practical tips if you are winging it.