Many airlines around the world use the Boeing 737 because it’s reliable and perfect for short to medium flights. Airlines like Southwest, Ryanair, American Airlines, and United Airlines have large fleets of 737s. This plane is popular with both budget and major carriers because it’s fuel-efficient and easy to maintain, making it a favorite for routes that don’t require long-range jets. Whether flying within a country or across nearby regions, the Boeing 737 is a common choice for many airlines.