A "Propfan" is a type of aircraft propulsion system that combines features of both propellers and jet engines. It uses large, advanced propeller blades that operate at high speeds, allowing for greater efficiency and reduced fuel consumption compared to traditional turboprop engines. Propfans are designed to provide thrust while minimizing noise and drag, making them suitable for commercial aviation. These engines are often referred to as open rotor engines because the blades are exposed and not enclosed like in conventional jet engines. Propfans have been explored for use in future aircraft designs, aiming to enhance performance and environmental sustainability in air travel.