Mike's Planes, Trains, and Automobiles on Instagram: "United Airlines Current Fleet Smallest to Largest #10 Boeing 737-900 and 900(ER) The Boeing 737 Next Generation, commonly abbreviated as 737NG, or 737 Next Gen, is a twin-engine narrow-body aircraft produced by Boeing Commercial Airplanes. Launched in 1993 as the third-generation derivative of the Boeing 737, it was produced from 1997 to 2019. The -900 is a stretched version to 138 ft. Because the −900 retains the same exit configuration of t