To reduce the chance of DVT when flying or other restrained activity, take one or two regular sized aspirins for a day or two if ASA doesn't give you gastric symptoms. Everyone should do that to protect themselves. A couple days of ASA won't give one bleeding problems. Frequent foot and ankle exercises are a good preventive maneuver or just walk around as often as possible. Since you are a MtF individual, wear support pantyhose. Not only feel good, the PH will help promote venous return from your lower extremeties.