A KC-10 Extender from Travis Air Force Base, Calif., parks on the base’s flightline Sept. 13, 2019. The KC-10 participated in the 2019 iteration of exercise Mobility Guardian, Air Mobility Command’s largest exercise designed to build and test the Mobility Air Force’s readiness to compete and win in contested operations against near-peer adversaries as outlined by the National Defense Strategy. (U.S. Air Force photo by Senior Airman Christian Conrad)