Turbofan engines are a type of jet engine commonly used in commercial aircraft. They work by drawing in air through a large fan at the front, which then splits the airflow into two paths: one goes into the engine core for combustion, while the other bypasses the core. This design allows for greater efficiency and quieter operation compared to traditional turbojet engines. The bypassed air provides additional thrust, making turbofan engines more fuel-efficient, especially at subsonic speeds. They are characterized by their large diameter fans and are essential for modern aviation, powering many popular aircraft models like the Boeing 737 and Airbus A320.