A U.S. Air Force F-16 Fighting Falcon pilot assigned to the 55th Expeditionary Fighter Squadron waits on the flightline during a hot pit refueling operation as part of an Agile Combat Employment exercise at an undisclosed location, Dec. 21, 2021. ACE is an operational concept that leverages networks of well-established and austere air bases, multi-capable Airmen, prepositional equipment and airlift to rapidly deploy, disperse and maneuver combat capability throughout a theater. (U.S. Air Force photo by Staff Sgt. Joseph Pick)