The Boeing 737NG is Boeing's 3rd generation and latest addition to their 737 lineup. The 737 is a short to medium range, single-isle airliner, which started production in 1996 and entered service in 1998. There are 4 basic variants to the 737NG, which can seat 110 and 210 passengers. It is also available as a cargo aircraft, a quick convertible aircraft, maritime patrol, military airborne radar, and a business jet. Over 4,500 737NG airframes have been sold and delivered around the world.