Boeing launched the 737-800 in 1994 as the stretched heart of the Next Generation family. It was meant to replace the 737-400 and take on the Airbus A320 head-on. The stretch added seats without adding much weight, so airlines earned more from every departure. It first flew on July 31, 1997, and German carrier Hapag-Lloyd began service in April 1998. Costs per seat fell sharply for every operator.
With 162 to 189 seats, a new larger wing and CFM56-7B engines, it landed almost perfectly in the sweet spot of the short-haul market. Nearly 5,000 were delivered before production moved to the MAX 8. Only a handful of airliner types have ever reached such numbers, and deliveries ran for more than two decades. That makes it the best-selling 737 version ever built. Few programs have matched the pace.
Ryanair built Europe's largest all-Boeing short-haul operation on more than 400 of them. Southwest, American, United, Delta, Qantas and Turkish Airlines made it their standard domestic jet. The airframe also led to the US Navy's P-8 Poseidon. Even now it is one of the most common aircraft in the sky at any given moment. Hundreds now fly again as 737-800BCF freighters, hauling packages for e-commerce networks.