I have sickle cell trait,am i at more of a risk for blood clots or embolism? if so how can i prevent them?

Minor risk: Your greatest danger comes from non-pressurized aircraft and anything else that lowers your oxygen tension substantially. You also need to know that you can't concentrate your urine and retain your sodium as well as other folks, so be careful exercising in the heat. The increased thrombus risk is minimal. Keep your legs active especially on long plane flights.

Sickle Trait: There is a slightly increased risk in this setting, but it is not large. You should strive to keep yourself well hydrated, get regular exercise, and avoid prolonged sedentary settings that may pre-dispose to clotting.