U.S. Air Force Airmen from the 52nd Fighter Wing hold orders while waiting to leave for a simulated deployment at Spangdahlem Air Base, Germany, Dec. 17, 2019. They participated in an Agile Combat Employment exercise, a developing concept of operations intended to ensure U.S. Air Forces in Europe are ready for potential contingencies. (U.S. Air Force photo by Airman 1st Class Valerie Seelye)