The 737-700 was added to the Next Generation planes when Southwest Airlines ordered one in November 1993. The -700 was based on the 737-300. It was brought into service in 1998. It replaced the 737-300. Its main rival is the A319. 126 people can fit into the 737-700 if there are two classes (first class and economy). However, 149 can fit in if the aircraft only has an economy class. Boeing launched the 737-700ER on January 30, 2006. "ER" stands for "extra range". This means that the plane can fly further than a normal 737-700. All Nippon Airways was the launch customer for the -700ER. It has the body of a 737-700, but the wings and landing gear of a 737-800. It can fly for 5,510 nautical miles (10,205 kilometers). 126 passengers can fit onto the plane.