The Boeing Next-Generation 737s jets are the most advanced single-aisle airplanes in the market today. While these new airplanes retain the characteristics that made the original 737 jet classics so popular worldwide - reliable, simple and economical to operate - they underwent dramatic revisions. The newer 737s respond to airline requests to combine advances - a longer, reshaped wing; new engines; and a taller tail - with commonality; pilots trained on earlier 737s can easily fly the newest model. In 2002 the 737 manufacturing process converted to a moving line system, replacing the station to station method of assembly pictured here.