How high does the military airborne jump from?

Typically in the United States tandem skydiving is done from 10,000' up to 14,000, with a few DZs offering exit altitudes of up to 18,000. In order to go above 14,000' MSL legally, all crew and passengers are required to be on supplemental oxygen. So, exit altitude above 14,000 above sea level you'll have an oxygen mask in the airplane, if not you're in violation of the Federal Aviation Regulations. The United States Parachute Association (USPA) indicates a minimum tandem exit altitude of 7,000' above ground level.