Almost all modern airplanes today use either a turbofan or a turboprop engine, both of which are a variation of turbojet engines. While both turbofan and turboprop engines are used in commercial aviation today, it has been proven time and again that turboprop engines can turn out to be far more advantageous in several situations.
A turboprop engine is basically an advanced variation a turbojet engine. In this variation, the shaft work that makes up the turbojet engine is used for driving a propeller through a reduction gear mechanism. The propeller reaction is responsible for creating most of the thrust in this type of engine while a negligible amount of usable energy is also generated. Moreover, in most types of turboprop engines, there is one or more stage of centrifugal compression used.
Despite the use of a turbojet engine as a base, the turboprop engine offers certain advantages over the other two types of engines. A large quantity of air is accelerated by a turboprop at a relatively low exhaust velocity. This makes a turboprop engine extremely fuel-efficient, but at the expense of airspeed. Hence, when used at a speed between 250 to 450 mph, a turboprop engine turns out to be the most fuel-efficient engine, especially when compared to turbojet and turbofan, giving remarkably excellent performance.
Another case in which a turboprop can be more advantageous is when you have to travel short distances. For routes that are less than 300nm, a turboprop can be the ideal engine choice, mainly because of the physics applications. Usually, a jet flies faster; as a result, it requires more distance or a wider arc to make a turn at both landing and take-off time. This will reduce the time of a short route flight enough to bring the flight time equal to that of a turbojet or turbofan engine.
In short, if you are using a turboprop engine at a speed between 250 to 450 mph, and you travel a route of less than 200nm, you can end up saving fuel worth $350 while increasing the total flight time by only six minutes. Therefore, when it comes to shorter routes and lower speeds, turboprop engines are definitely a far more fuel-efficient choice.