The newest member of the Boeing Next-Generation 737 family, the 737-900ER (Extended Range), earned type certification from the U.S. Federal Aviation Administration on April 20.

The 737 derivative incorporates an extra pair of exit doors to increase the maximum passenger capacity, a flat aft-pressure bulkhead to increase interior volume, a two-position tailskid for improved takeoff and landing capability, wing strengthening changes to accommodate the 13,500 pound maximum takeoff weight increase, enhancements to the leading and trailing edge flap systems for improved takeoff and landing capability, and optional Blended Winglets and auxiliary fuel tanks that increase the range of the 737-900ER to 3,200 nautical miles (5,925 km).

The airplane is certified to carry up to 220 passengers in a single-class configuration.

On July 18, 2005, Indonesia's Lion Air launched the higher capacity, longer range Next-Generation 737-900ER with an order for 30 airplanes. Airlines have ordered more than 100 Next-Generation 737-900ERs to date.