World War II was the first war to see extensive use of aircraft for bombing enemy targets. The German Luftwaffe bombed military and civilian targets indiscriminately during the invasion of Poland in 1939, but refrained from using similar tactics on French and British targets in the early years of World War II. On March 16, 1940, German bombers killed a single civilian while conducting their first bombing of an Allied land target over the British Orkney Islands.

The Strategic Bombing War Begins

Britain's Royal Air Force retaliated on March 19, 1940 by sending a squadron of 50 aircraft, including heavy Whitley bombers, to bomb a German seaplane factory on Hornum, located on the German Frisian Islands. The first large scale bombing of the German mainland commenced two months later, on May 15, 1940. The first mainland targets were industrial sites in the Ruhr region. Soon after, both Allied and German bombers were used to target civilian areas. British Prime Minister Winston Churchill went so far as to publicly declare the goal of British strategic bombing was the "de-housing" of German industrial workers.