U.S. Air Force Master Sgt. Christopher Hoopes, 1st Operations Group Aerospace and Operational Physiology flight chief instructs an F-22 Raptor Pilot at Joint Base Langley-Eustis, Virginia, June 13, 2019. While operating the Reduced Oxygen Breathing Device, the AOP technicians speak with the individual training to keep them active, all while monitoring their vitals as they reduce the amount of oxygen the individual has to breathe. (U.S. Air Force photo by Senior Airman Tristan Biese)