The versatility and reliability of the Boeing 727 - the first trijet introduced into commercial service - made it the best-selling airliner in the world during the first 30 years of jet transport service. Several jetliners, including the Boeing 707, were developed before the 727, but none came close to its sales record.

Production of the 727 extended from the early 1960s to August 1984 -- a remarkable length of time, considering the original market forecast was for 250 airplanes. As it turned out, 1,831 were delivered. As of December 1998, nearly 1,500 of the reliable aircraft were still in service.

Introduced into service in February 1964, the 727 trijet became an immediate hit with a fuselage width the same as the 707. With sophisticated, triple-slotted trailing edge flaps and new leading-edge slats, the 727 had unprecedented low-speed landing and takeoff performance for a commercial jet and could be accommodated by smaller airstrips than the 707 required.

The 727, like all Boeing jetliners, was continually modified to fit the changing market. It began with the -100 series, of which 407 were sold. This was followed by the -100C convertible that featured a main-deck side cargo door, allowing it to carry either cargo pallets or passengers - or a combination of both - on the main deck. Boeing built 164 of these.

Later performance improvements for the 727 included another gross weight boost, from a maximum 170,000 pounds (77,122 kg) to 191,000 pounds (86,600 kg) for the advanced version. On February 3, 1972, another increase to 208,000 pounds (94,348 kg) was announced. The 727's highest gross weight was eventually raised to 210,000 pounds (95,300 kg).

The 727 became the best-selling airliner in history when orders passed the 1,000 mark in September 1972. By January 1983, orders reached 1,831. On Dec. 5, 1977, the worldwide 727 fleet carried its one-billionth (1,000,000,000) passenger - a mark never attained before by a commercial aircraft. By September 1995, the number had reached 4.2 billion.