Many things affect here, prop, engine output, wingloading, aerodynamics ( drag, wingfoil, cross section, geometry of things etc. ), overall cleaness of the design and most of all pilot skills.

Very interesting to know is that Mustang had lot less wingloading than Me-109 or FW 190D and thus it had a good range ( fuel economy ). Also large prop and radiator design + wingfoil ( laminar ) affected and good drop tanks….charger and carburettor….100 octane fuel….smaller cubature engine…