The Boeing 737 is a short-to medium-range twinjet narrow-body airliner. Originally developed as a shorter, lower-cost twin-engined airliner derived from Boeing's 707 and 727, the 737 has developed into a family of ten passenger models with a capacity of 85 to 215 passengers.oeing's BBJ3 is based on the 737-900ER. The BBJ3 has 1,120 square feet (104 m 2) of floor space, 35% more interior space, and 89% more luggage space than the BBJ2. It has an auxiliary fuel system, giving it a range of up to 4,725 nautical miles (8,751 km), and a Head-up display.