Turboprop and turbofan engines have low specific fuel consumption and are used on long range airliners. If we can run the engine at a low throttle setting, producing a minimum amount of thrust we can also fly longer. But we must produce enough thrust to equal drag in a cruise condition. On this page, we have taken a very simple view of aircraft range - for academic purposes. In reality, calculating the range is a complex problem because of the number of variables.
Extra fuel is expended in climbing to altitude and in maneuvering the aircraft.