A monoplane has inherently the highest efficiency and lowest drag of any wing configuration and is the simplest to build. However, during the early years of flight, these advantages were offset by its greater weight and lower manoeuvrability, making it relatively rare until the 1930s. Since then, the monoplane has been the most common form for a fixed-wing aircraft.
The inherent efficiency of the monoplane can best be realized in the unbraced cantilever wing which carries all structural forces internally. By contrast, a braced wing has additional drag from the exposed bracing struts or wires, lowering aerodynamic efficiency. On the other hand, the braced wing has greater structural efficiency and can be made much lighter. This in turn means that for a wing of a given size, bracing allows it to fly slower with a lower-powered engine, while a heavy cantilever wing needs a more powerful engine and can fly faster.
Besides the general variations in wing configuration such as tail position and use of bracing, the main distinction between types of monoplane is how high up the wings are mounted in relation to the fuselage.
A low wing is one which is located on or near the base of the fuselage.
Placing the wing low down allows good visibility upwards and frees up the central fuselage from the wing spar carry-through. By reducing pendulum stability, it makes the aircraft more manoeuvrable, as on the Spitfire; but aircraft that value stability over manoeuvrability may then need some dihedral.