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 CFM56, and is 40 dB quieter than JT3D engines that are being replaced. The first commercial orders for the 707 came on October 13, 1955, when Pan Am committed to 20 707s and 25 Douglas DC-8s, dramatically increasing their passenger capacity (in available revenue passenger seat-miles per hour/per day) over its existing fleet of propeller aircraft. The competition between the 707 and Douglas DC-8 was fierce. Pan American ordered these planes, when and as they did, so that they would be the operators of the "first-off" production line for each aircraft type. Until their initial batch of the aircraft had