Master Sgt. Kristofer Reyes, a 99th Airlift Squadron flight engineer, stands at parade rest in front of a C-37A and awaits the arrival of a U.S. senior elected leader at Joint Base Andrews, Md., June 7, 2016. In addition to monitoring and maintaining the mechanical and electrical systems on the C-37A, a highly modified Gulfstream G5 aircraft, flight engineers are also responsible for greeting their customers, which are typically the U.S. vice president, cabinet members, combatant commanders, and other senior military and elected leaders. (U.S. Air Force photo/Senior Master Sgt. Kevin Wallace)