aircraft by final delivery in 1978. Most original JetStars have been retired, but many 731 JetStars and JetStar IIs are still flying in various roles, mainly as corporate and private jets. Design The JetStar has a fairly typical business jet design layout, with a swept wing and a cruciform tail. The wing has a 30° sweepback and features large fuel tanks at about half-span, extending some distance in front and behind the wing. The wings hold 10,000 pounds of fuel, and each slipper tank holds 4,000 pounds of fuel for a total fuel load of 18,000 pounds. The wing also includes leading edge flaps (not slats) along the front of the wing outboard of the tanks (these leading edge flaps reduce the stalling speed by an additional three knots), while double-slotted trailing edge flaps span the entire rear surface inboard of the ailerons. The wing incorporates inflatable rubber deicing boots for the removal of ice accumulated in flight. The horizontal stabilizer is mounted nearly halfway up the fin to keep it clear of the engines' jet blast. One feature is that the horizontal stabilizer is trimmable by pivoting the entire tail fin and stabilizer assembly, which has a distinctive unpainted area at the base of the fin that is noticeable in most pictures. The JetStar does not have any tail deicing capability, nor was it required for certification. A speed brake is located on the underside of the fuselage to aid deceleration for landing. The original prototypes used a tricycle landing gear with one wheel per leg, but after an accident in 1962 the nose gear was modified with two tires. The JetStar is a relatively heavy aircraft for its class, at 44,500 lb (19,278 kg). Maximum cruising speed is Mach 0.8, or 567 mph (912 km/h) at 21,000 ft (6,401 m). Range is typically quoted as 2,500 mi (4,023 km) with a 3,500 lb (1,588 kg) payload. Typically, interiors feature seating for eight with a full-sized lavatory, or a slightly denser arrangement for ten. The JetStar is one of the few aircraft of its class which allow a person to walk upright in the cabin, although to do this the aisle is sunk slightly so that the seats are raised on either side. The windows are relatively large. Operational history The first prototype served as the personal transport of Lockheed's Vice President of Advanced Development Projects Kelly Johnson for