Which airline introduced the first commercial Boeing 737-800 service?

Hapag-Lloyd Flug introduced the first commercial Boeing 737-800 service.

The German leisure airline became the launch operator of the 737-800, a longer-range and higher-capacity member of Boeing’s 737 Next Generation family. The aircraft entered commercial service with Hapag-Lloyd Flug in 1998.

The 737-800 improved on earlier 737 models with updated engines, a redesigned wing, a modernized cockpit, and greater range. Its size and operating economics made it especially popular with both low-cost and traditional airlines.

Hapag-Lloyd Flug later became part of the German leisure-airline group that developed into TUIfly. The 737-800 went on to become one of the most widely used commercial aircraft variants in the world.