Oil campaign of World War II in the context of Bombing of Hamburg

The Blockade of Germany (1939–1945), also known as the Economic War, involved operations carried out during World War II by the British Empire and by France in order to restrict the supplies of minerals, fuel, metals, food and textiles needed by Nazi Germany – and later by Fascist Italy – in order to sustain their war efforts. The economic war consisted mainly of a naval blockade, which formed part of the wider Battle of the Atlantic, but also included the bombing of economically important targets and the preclusive buying of war materials from neutral countries in order to prevent their sale to the Axis powers.

• The first period, from the beginning of European hostilities in September 1939 to the end of the "Phoney War", saw both the Allies and the Axis powers intercepting neutral merchant ships to seize deliveries en route to their respective enemies. Naval blockade at this time proved less than effective because the Axis could get crucial materials from the Soviet Union until June 1941, while Berlin used harbours in Spain to import war materials into Germany.
• The second period began after the rapid Axis occupation of the majority of the European landmass (Scandinavia, Benelux, France and the Balkans) in 1940–1941, resulting in Axis control of major centres of industry and agriculture.
• The third period started in December 1941 after the attack on Pearl Harbor by the Imperial Japanese Navy Air Service brought the U.S. officially into the European war.
• The final period came after the tide of war finally turned against the Axis after heavy military defeats up to and after D-Day in June 1944, which led to gradual Axis withdrawals from the occupied territories in the face of the overwhelming Allied military offensives.

World War II (1939–1945) involved sustained strategic bombing of railways, harbours, cities, workers' and civilian housing, and industrial districts in enemy territory. Strategic bombing as a military strategy is distinct both from close air support of ground forces and from tactical air power. During World War II, many military strategists of air power believed that air forces could win major victories by attacking industrial and political infrastructure, rather than purely military targets. Strategic bombing often involved bombing areas inhabited by civilians, and some campaigns were deliberately designed to target civilian populations in order to terrorize them or to weaken their morale. International law at the outset of World War II did not specifically forbid the aerial bombardment of cities – despite the prior occurrence of such bombing during World War I (1914–1918), the Spanish Civil War (1936–1939), and the Second Sino-Japanese War (1937–1945).

Strategic bombing during World War II in Europe began on 1 September 1939 when Germany invaded Poland and the Luftwaffe (German Air Force) began bombing Polish cities and the civilian population in an aerial bombardment campaign. As the war continued to expand, bombing by both the Axis and the Allies increased significantly. The Royal Air Force, in retaliation for Luftwaffe attacks on the UK which started on 16 October 1939, began bombing military targets in Germany, commencing with the Luftwaffe seaplane air base at Hörnum on the 19–20 March 1940. In September 1940 the Luftwaffe began targeting British civilians in the Blitz. After the beginning of Operation Barbarossa in June 1941, the Luftwaffe attacked Soviet cities and infrastructure. From February 1942 onward, the British bombing campaign against Germany became even less restricted and increasingly targeted industrial sites and civilian areas. When the United States began flying bombing missions against Germany, it reinforced British efforts. The Allies attacked oil installations, and controversial firebombings took place against Hamburg (1943), Dresden (1945), and other German cities.

The Allied bombing of Hamburg during World War II included numerous attacks on civilians and civic infrastructure. As a large city and industrial centre, Hamburg's shipyards, U-boat pens, and the Hamburg-Harburg area oil refineries were attacked throughout the war.

As part of a sustained campaign of strategic bombing during World War II, the attack during the last week of July 1943, code named Operation Gomorrah, created one of the largest firestorms raised by the Royal Air Force and United States Army Air Forces in World War II, killing an estimated 34,000 people in Hamburg, wounding 180,000 more, and destroying 60% of the city's houses.

Operation Tidal Wave was an air attack by bombers of the United States Army Air Forces (USAAF) based in Libya on nine oil refineries around Ploiești, Romania, on 1 August 1943, during World War II. It was a strategic bombing mission and part of the "oil campaign" to deny petroleum-based fuel to the Axis powers. The mission resulted in "no curtailment of overall product output".

This operation was one of the costliest for the USAAF in the European Theater, with 53 aircraft and 500 aircrewmen lost. It was proportionally the most costly major Allied air raid of the war, and its date was later referred to as "Black Sunday". Five Medals of Honor and 56 Distinguished Service Crosses, along with numerous other awards, went to Operation Tidal Wave crew members. A 1999 research report prepared for the Air War College at Maxwell Air Force Base in Alabama concluded that the bombing campaign in Ploiești was "one of the bloodiest and most heroic missions of all time". One of the downed American planes crashed into a female prison in Ploiești, resulting in about half of the civilian casualties from the total of 101 killed and 238 injured.