U.S. Air Force Airmen sit on the back of a C-130J Super Hercules aircraft while flying over Normandy, France, as part of a D-Day anniversary event June 6, 2021. The “D” in D-Day isn’t short for departure or decision. As early as World War I, the U.S. military used the term D-Day to designate the launch date of a mission. (U.S. Air Force photo by Airman Edgar Grimaldo)