The best-selling Boeing 737 started as a smaller, short-range jet. Models 737-300, -400, and -500 were followed by the Next-Generation 737-600, -700, -800, -900, and the luxurious Boeing Business Jet. The Boeing Next-Generation 737s are the most advanced single-aisle airplanes in the market today. While these new airplanes retain the characteristics that made 737 classics so popular worldwide - reliable, simple and economical to operate - they underwent dramatic revisions. In 2002 the 737 manufacturing process converted to a moving line system, replacing the station to station method of assembly pictured here.