U.S. Air Force Airman 1st Class Jorge Villarreal, a loadmaster assigned to the 41st Airlift Squadron, inspects container delivery systems at Alpena Combat Readiness Training Center, Michigan, May 21, 2021. Conducted biennially, Mobility Guardian is the Air Force’s only formal, Total Force, service-level mechanism for assessing and validating capabilities in Rapid Global Mobility missions specified and implied within the 2018 National Defense Strategy. (U.S. Air Force photo by Staff Sgt. Joseph Pick)