Boeing 707 lb (57.8 kN) with water injection. Maximum takeoff weight was 247,000 lb and first flight was on December 20, 1957. Major orders were the launch order for 20 707-121 aircraft by Pan Am and an American Airlines order for 30 707-123 aircraft. The first revenue flight was on October 26, 1958; 56 were built, plus seven short-bodied −138s; the last −120 was delivered to Western in May 1960. The 707-138 was a −120 with a fuselage 10 ft shorter than the others, with 5 ft (three frames) removed ahead and behind the wing, giving increased range. Maximum takeoff weight was
Boeing 707 the same 247,000 lb as the standard version. It was a variant for Qantas, thus had its customer number 38. The seven −138s were delivered to Qantas June–September 1959 and first carried passengers that July. The 707-120B had Pratt & Whitney JT3D-1 turbofan engines, which were quieter, more powerful, and more fuel-efficient, producing each, with the later JT3D-3 version giving . (This thrust did not require water injection, eliminating both the system and 5000–6000 lb of water.) The −120B had the wing modifications introduced on the 720 and a longer tailplane; a total of 72 were built, 31 for American