Yep, I should add in that flights are a very common catalyst for DVTs. So common that they often call it "economy class syndrome" (http://www.medicinenet.com/script/main/art.asp?articlekey=15...) - my clot was possibly catalyzed by a flight but that is not yet conclusive. Needless to say, try to move around as much as possible on a flight (even it means wiggling your toes or legs), and stay healthy (you are much more likely to get a DVT from a flight if you are already unhealthy).