The 737 Next Generation comprises the four -600, -700, -800, and -900 models, ranging from 102 ft (31.09 m) to 138 ft (42.06 m) in length. Boeing Business Jet versions of the 737 Next Generation are also produced.The 737 series is the best-selling jet commercial airliner.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.