On July 10th, 1940, the German air force, the Luftwaffe, invaded Britain without the help of the army or navy. This is because the army and navy had suffered heavy losses in previous battles. The Luftwaffe's goal was to gain air superiority over the Royal Air Force (RAF) in Britain, which would make it much easier to annex Britain when the army and navy are ready. Unfortunately for Germany, Britain had many advantages over Germany in the Battle of Britain, the biggest advantages being an effective land based air defence system, their pilots were trained better, they had a better Air Marshal (Air Marshal Hugh Dowding), and help from other countries like Canada. Germany wasted most of July waiting for the British surrender that was never going to come, as this wasted time gave Britain more time to prepare for the battle. Germany also never tried to figure out Britain's vulnerabilities which made the Luftwaffe unprepared against the RAF when they attacked in August.
At first, the Luftwaffe were attacking Britain's military bases and industrial complexes, but when the RAF started to bomb Berlin, the Luftwaffe started bombing civilian area's like shopping centres. This made civilians move into the subway so that they could be safe from the bombs being dropped. The Luftwaffe also started larger attacks rather than their original approach of more small attacks.
Canada, along with some other countries, had an impact on the Battle of Britain. Canada sent around 100 Royal Canadian Air Force (RCAF) pilots to fight in the battle (the exact number is unknown). They fought in the No. 1 and 242 squadrons of the RAF.
The destruction of the Dockland area in London from a German bomber on September 17, 1940