Rescue Aircraft sent ahead of single-engine jet fighters being delivered over ocean regions. The "Duckbutt" orbits along critical route segments, such as those for air refueling, and aids in rescuing flight crews, should a fighter need to ditch.
Movements of single engine fighters take place during repositioning to military exercise locations overseas, or the delivery of these planes from their overseas bases to repair depots. Bases on the Islands of Hawaii, Guam, and Okinawa are staffed with USAF Aircraft Delivery personnel. It is their job to coordinate with each agency which will service, repair, control, or Air Refuel the aircraft, making sure all of these operations run smoothly. One aspect of these efforts entails launching a "Duckbutt" aircraft (Usually an HC-130 "Hercules" four-engine turboprop) to provide rescue services for the crews if they ditch the plane.