Passage: In response to Hitler's actions, two days later, on 3 September, after a British ultimatum to Germany to cease military operations was ignored, Britain and France declared war on Germany. In the spring of 1940, Germany conquered Denmark and Norway, the Netherlands, Belgium, Luxembourg, and France forcing the French government to sign an armistice after German troops occupied most of the country. The British repelled German air attacks in the Battle of Britain in the same year. In 1941, German troops invaded Yugoslavia, Greece and the Soviet Union. By 1942, Germany and other Axis powers controlled most of continental Europe and North Africa, but following the Soviet Union's victory at the Battle of Stalingrad, the allies' reconquest of North Africa and invasion of Italy in 1943, German forces suffered repeated military defeats. In June 1944, the Western allies landed in France and the Soviets pushed into Eastern Europe. By late 1944, the Western allies had entered Germany despite one final German counter offensive in the Ardennes Forest. Following Hitler's suicide during the Battle of Berlin, German armed forces surrendered on 8 May 1945, ending World War II in Europe. After World War II, former members of the Nazi regime were tried for war crimes at the Nuremberg trials.In what later became known as The Holocaust, the German government persecuted minorities and used a network of concentration and death camps across Europe to conduct a genocide of what they considered to be inferior peoples. In total 17 million were systematically murdered, including 6 million Jews, between 220,000 and 1,500,000 Romani, 275,000 persons with disabilities, thousands of Jehovah's Witnesses, thousands of homosexuals, and hundreds of thousands of members of the political and religious opposition from Germany, and occupied countries (Nacht und Nebel). Nazi policies in German occupied countries resulted in the deaths of 2.7 million Poles, 1.3 million Ukrainians, 1 million Belarusians and an estimated 3.5 million Soviet war prisoners....

Question: Which troops attempted to execute air attacks on the British in 1940?
German