The Boeing 737 is a popular single-aisle aircraft used all over the world. It is designed for short and medium-distance flights and is known for its reliability and efficiency. The 737 can carry between 185 and 440 passengers, depending on the version and cabin layout. There are several models of the 737, including the older Classic and Next Generation versions, as well as the newer 737 MAX. The latest models offer quieter engines, better fuel efficiency, and modern cabin features like Wi-Fi and LED lighting.