The Battle of Britain was one of the most decisive battle of World War II. Although nearly every battle of the war involved aircraft and aerial battle, this was the only battle which was fought exclusively in the air. By June 1940, France had fallen to German control. All that still stood against Germany was England to the west and Russia to the east. America had not yet joined the war. .
As Hitler's military prepared to continue their conquest by moving into England, they knew that doing so would be impossible without air superiority. The greatest and longest aerial battle would soon commence. Up to this point in the war, Germany had relied on it's aerial attacks and bombing to soften their targets. Germany was up to this point, unstoppable. Unknown to them however, they would soon meet their first true challenge with that of the Royal Air Force (RAF) of Britain. The steamroller which was the German military would soon be proven stoppable. .
June 1940, the United Kingdom stood alone as the last surviving European nation. Germany had conquered Europe in mass and now had only the English Channel between them and taking England as well. Hitler's intention was to force the English to surrender through blockade, bombing and as a last resort, invasion. To achieve this, Hitler knew he needed air superiority. If Germany controlled the skies, heavy bombing campaigns could be mounted for an invasion of ground forces. This meant however, defeating the RAF in full. Germany could not launch an invasion of ground forces, as the British Royal Navy was very large and powerful, with strategic positioning around the U.K. .
The Luftwaffe had three Luftflotten (air fleets) spread north to south along the western European coast. Roughly 2,800 German aircraft were available for the aerial operations. Two-thirds of those were bombers. The RAF had about 650 aircraft total with around 1,300 pilots. Greatly outnumbered, the RAF knew this would be a difficult battle and that they had the disadvantage.