When Orville and Wilbur Wright evolved the successful man-carrying aeroplane, they saw in it a machine to prohibit war; by 1914 there were many who still thought it useless for waging war—though they were soon to be disproved. In 1940, air supremacy became the key to the future course of a new world conflict; and in the two decades since then, air power has played a vital part in preventing small conflicts from developing into global proportions.