A monoplane is a fixed-wing aircraft with a single main wing plane, in contrast to a biplane or other multiplane, each of which has multiple planes. 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.