The Douglas DC-5 entered service with the U.S. Navy and seven were built as R3Ds. Three R3D-1s became 16-seat personnel carriers, and the four R3D-2s with the U.S. Marine Corps became 22-seat paratrooper versions of the plane. Two civilian DC-5s later joined the U.S. Army Air Forces (USAAF) as C-110s.