deadheading
n.— «“Deadheading it,” or sleeping, during the trip is probably the only rest they’ll get on their 16- to 18-hour medevac mission.» —“Caring for the seriously wounded wears on Air Evacuation Squadron crew” by Scott Schonauer in Balad Air Base, Iraq Stars and Stripes Mar. 31, 2005. (source: Double-Tongued Dictionary)