B737-800

The Boeing 737 Next Generation, commonly abbreviated as 737NG, is the name given to the −600/-700/-800/-900 series of the Boeing 737 airliner. It is the third generation derivative of the 737, and follows the 737 Classic (−300/-400/-500) series, which began production in the 1980s. They are short- to medium-range, narrow-body jet airliners. Produced since 1996 by Boeing Commercial Airplanes, the 737NG series includes four variants and can seat between 110 and 210 passengers.

As of March 2017, a total of 7,119 737NG aircraft have been ordered, of which 6,316 have been delivered. The remaining orders are in the -700, -700 BBJ, -800, and -900ER variants. The 737NG's primary competition is with the Airbus A320 family. Upgraded and re-engined models in development as the 737 MAX series are to eventually supplant the 737NG, with the first 737 MAX to be delivered in 2017.

Prompted by the development of the Airbus A320, which incorporated ground-breaking technologies such as fly-by-wire, in 1991 Boeing initiated development of an updated series of aircraft. After working with potential customers, the 737 Next Generation (NG) program was announced on November 17, 1993. The 737NG encompasses the −600, −700, −800 and −900 variants, and is to date the most significant upgrade of the airframe. The performance of the 737NG is essentially that of a new airplane, but important commonality is retained from previous 737 generations. The wing was modified, increasing its area by 25% and span by 16 ft (4.88 m), which increased the total fuel capacity by 30%. New quieter and more fuel-efficient CFM56-7B engines were used. These improvements combine to increase the 737's range by 900 nmi, permitting transcontinental service. A flight test program was operated by 10 aircraft: 3 -600s, 4 -700s, and 3 -800s.

The passenger cabin of the 737 Next Generation improved on the previous style interior of the Boeing 757-200 and the Boeing 737 Classic by incorporating select features from the 777, with larger, more rounded overhead bins and curved ceiling panels. The interior of the 737 Next Generation also became the standard interior on the Boeing 757-300, and subsequently became optional on the 757-200.