In-flight testing is conducted to certify a Negatively Pressurized Conex prototype at Joint Base Charleston, S.C., April 30, 2020. The NPC was rapidly developed and designed to fit inside both C-5 and C-17 aircraft to enable safe transport of up to 28 patients, as well as teams of medical professionals to medical facilities around the globe. (U.S. Air Force photo by Staff Sgt. Chris Drzazgowski)