With their views of strategic bombing, they built long-range bombers to implement their plans. Once Germany became a threat, the Royal Air Force began a large expansion. They set up various airfields and increased the number of squadrons in the air force. Newly developed radar was combined with communication centers to direct their fighter defenses. Following the outbreak of war against Germany, the Royal Air Force underwent rapid expansion. This expansion implemented the training of British Commonwealth nations such as Canada. In Europe, the Royal Air Force was in operational control of Commonwealth aircrews and squadrons. The Royal Air Force had three major combat commands based in the United Kingdom. The Royal Air Force Fighter Command’s task was to defend the United Kingdom. The Royal Air Force Bomber Command operated bombers that would be used offensively against the enemy. The Royal Air Forces Coastal Command protected Allied shipping and attacked enemy ships. There were two areas of attack in which Bomber Command Participated. One of these areas was the strategic bombing against German war production, and the other was the bombing of coastal waters to prevent U-boats from freely