The Boeing 737-900 is the longest variant of the 737 Next Generation (NG) family, designed to offer increased passenger capacity. It was launched by Boeing in November 1997, with Alaska Airlines serving as the launch customer, taking its first delivery in 2001. While it provided more floor space than its predecessors, its initial design did not include additional emergency exits beyond what was required for the smaller 737-800, which limited its maximum passenger seating to 189 passengers despite its greater length. This initial limitation led to the development of its successor, the 737-900ER (Extended Range), which addressed this issue with extra exit doors and other enhancements to fully leverage its longer fuselage. The 737-900 typically seats between 177 and 189 passengers in a two-class configuration and is commonly used for short-to-medium-haul routes.