I'm 5'11" 295 lbs & obesity can be a dvt risk factor on long flights. my flts are 3:50 & 85 mins gate to gate. if i walk every 30 mins should i be ok?

Great idea: Have you had deep venous thrombosis in the past? If not, this sounds like a protective plan. Standing up once in a while in flight allows is also good. If you can't stand on the plane than flex and relax your gluteal (butt) muscles as well as your calves. Have a good Flight.

You can also do seat: ed chair exercises to stretch your legs, calves, ankles, feet and do rotational, flex/extend (pointiflex) your feet and that will move the fascia/lymphatics from anterior/posterior direction and help circulation. They often don't let you walk on the plane during the first 20 minutes or last, or not at all on very short commuters. So get an aisle seat so you can walk, and stretch together.

Walking helps: The parameters you listed certainly could make it easier to get a DVT on such a long flight. Walking every thirty minutes should minimize that risk. Wiggling your feel while sitting will help even more.

Air travel: Air travel related blood clots is a real potential problem. This has a do with prolonged sitting and increased altitude in the plane despite the fact that the cabin is pressurized. Walking around during the trip may be of help, but the best treatment is using a support or compression stocking during any airplane travel. This works to stimulate the venous blood flow back towards the heart