Which engine combines the air-moving efficiency of a turbofan with the thrusting efficiency of a propeller?

The propfan engine effectively merges the advantages of turbofan engines and propellers, achieving high levels of air-moving efficiency typical of turbofans while also delivering thrust similar to that of propellers. This design enables propfans to operate efficiently at subsonic flight speeds, making them ideal for regional and transport aircraft. They have large, wide blades that operate at slower tip speeds compared to traditional turbojet designs, reducing drag and improving fuel efficiency.

In contrast, turboprop engines, while similar in that they use a propeller, generally do not provide the same level of efficiency at higher speeds as propfans do. Additionally, ramjets and scramjets are specifically designed for high-speed flight and generally do not operate efficiently at lower speeds, making them unsuitable for the context of this question. Turbine engines encompass a broad category that includes various designs, but without the specific integration of turbofan and propeller efficiencies found in propfans.