Including combatants from other countries
Battle of Britain is the name commonly given to the effort by the German Luftwaffe to gain air superiority over the Royal Air Force (RAF), before a planned sea and airborne invasion of Britain (Operation Sealion) during the Second World War. Neither Hitler nor the Wehrmacht believed it possible to carry out a successful amphibious assault on the British Isles until the RAF had been neutralized. Secondary objectives were to destroy aircraft production and ground infrastructure, to attack areas of political significance, and to terrorize the British people with the intent of intimidating them into seeking an armistice or surrender.
British historians date the battle from 10 July to 31 October 1940, which represented the most intense period of daylight bombing. German historians usually place the beginning of the battle in mid-August 1940 and end it in May 1941, on the withdrawal of the bomber units in preparation for the attack on the USSR. The failure of Nazi Germany to destroy Britain's air force, or to break the spirit of the British government or people, is considered the Third Reich's first major defeat. Some historians have argued no invasion could have succeeded; given the massive superiority of the Royal Navy over the Kriegsmarine, Sealion would have been a disaster. They argue the Luftwaffe would have been unable to prevent decisive intervention by RN cruisers and destroyers, even with air superiority.
The Battle of Britain was the first major battle to be fought entirely by air forces. It was the largest and most sustained bombing campaign yet attempted, and the first real test of the strategic bombing theories developed since the previous World War.