The United States of America was drawn into the Second World War in December 1941. Immediately afterwards steps were taken to increase the bombing offensive against Germany. Until that time this offensive has been executed exclusively by the British Royal Air Force, mainly at night. A small group of American staff officers flew to England, set up a headquarters close to that of Royal Air Force Bomber Command at High Wycombe, and started the buildup of the United States Eighth Army Air Force. In the first half of 1942 the first Bombardment Groups arrived in England, and after a few attacks by medium bombers, the first attack by heavy bombers, a mere twelve B-17s, was made on the Rouenz marshaling yards on August 17, 1942.
Although the Royal Air Force had found out early in the war that daylight bombing raids resulted in heavy losses, the United States Army Air Force staff officers stuck to the concept of daylight precision bombing. With the heavy armament of their bombers, the B-17 "Flying Fortresses" and B-24 "Liberators", they believed they could battle their way towards any target, bomb it accurately with the Norden bombsight, and get away. This theory was put to the test over Rouen, starting on this day, August 17, 1942.
On January 27, 1943 the first mission to Germany itself took place. Despite severe setbacks at times the Americans doggedly stuck to their daylight bombing. Gradually they succeeded in sapping the strength of the German Luftwaffe badly and, at the same time, increasing their own numbers to such an extent that the concept became tenable. In May 1943 the Combined Chiefs of
Staff had decided in favor of the so-called "Pointblank directive". This directive meant that only those targets were selected whose destruction would paralyze Germany's war effort and economy. Six target systems were proposed, comprising 76 precision targets, to be destroyed by heavy bombers. One of these target systems was the German oil industry. The first priority, however, was the destruction of the German Luflwaffe. Therefore, the first year of operations mainly saw attacks on airfields and the aircraft industry.
In May 1944 the large-scale attacks on the oil industry began and immediately proved very successful. Due to its limited natural resources, Germany relied heavily on synthetic fuel. The bombing raids on the plants wrought heavy destruction. Evidence of the damage was clearly visible in reconnaissance pictures and evident from reports from returning bomber crews. The German economy was certainly put under a great strain, as reports from agents indicated. The intensity of the offensive was stepped up. In May 1944 the strategic bombers dropped some 5,100 tons of bombs on oil targets. In August this tonnage had risen to 26,300 and in November the climax was reached, no less than 35,000 tons were dropped on numerous oil installations. Comparing these numbers with the German records on production and stocks of gasoline and diesel oil it is apparent that these attacks were very successful. On November 2, 1944 almost the entire might of the Eighth Air Force would be directed to oil installation again