When the hum of engines could be heard over the skies of London on 7 September 1940, it was the start of an onslaught that would push Britain to the brink. The Blitz had begun, and as aircraft went up against aircraft, there was a fight for the nation. It was a time of iconic combat planes - the legendary Spitfire was born, facing off against the Third Reich's famous Messerschmitt BF 109G. But it wasn't a new spectacle. The first fighter aircraft the world had ever seen were built in French fields about 25 years before. Since then, countries have raced to improve flight technology to gain control of the skies. In the World's Greatest Military Aircraft, climb into the cockpit of the world's earliest combat aircraft, from the French Voisin III to the German Albatross D.VA, as well as some of Britain's early forays into flight; go nose to nose with iconic fighter planes and bombers from the Second World War, including the Hawker Hurricane, P-51 Mustang, Mitsubishi A6M 'Zero', Avro Lancaster and B-17 Flying Fortress; and take to the skies with post-world war aircraft like the United States' F-14D Tomcat, Blackburn Buccaneer S2 and F-15 Eagle, the crowning jewel of the US Air Force.