A warning sign is posted outside an airdrop zone, April 3, 2020, at the Sooner Drop Zone, Oklahoma. The purpose of the airdrop mission is to provide C-17 Globemaster III aircrews with realistic training scenarios, which consists of on-and-off loading of general cargo and vehicles as well as aerial delivery materials such as pallets, for airdrop training. (U.S. Air Force photo by Airman 1st Class Breanna Klemm)