The aeroplane, of which a practical version first flew in December 1903, was visualized by its inventors, the Wright brothers, as a means of enlarging peaceful communication between peoples. Its military uses were quickly grasped by others and it served as a scout, fighter, and eventually bomber during World War I. By the outbreak of World War II, all advanced states had organized, large military air forces, chiefly dedicated to bombardment, which exponents of air power believed would win wars independently of action by sea or land. The operations of the air forces in World War I, between the wars and during World War II are the subject of this narrative history.