What can increase a person's risk for developing blood clots during travel?

A person's risk of developing a blood clot while traveling can be increased if they are older, they are overweight, they smoke, and if they are going to sit for a long period of time without exercising their muscles, and it could be either air travel or ground travel for that purpose. Certain medical conditions, if present, can also increase their risk, most commonly cancers, family history of blood clots, any hormone replacement therapies, birth control pills.