Combined Bomber Offensive
The Combined Bomber Offensive was an Allied offensive of strategic bombing during World War II in Europe. The primary portion of the CBO was directed against Luftwaffe targets which were the highest priority from June 1943 to 1 April 1944. The subsequent highest priority campaigns were against V-weapon installations and petroleum, oil, and lubrication plants. Additional CBO targets included railyards and other transportation targets, particularly prior to the invasion of Normandy and, along with army equipment, in the final stages of the war in Europe.
The British bombing campaign was chiefly waged by night by large numbers of heavy bombers until the latter stages of the war when German fighter defences were so reduced that daylight bombing was possible without risking large losses. The US effort was by day – massed formations of bombers with escorting fighters. Together they made up a round-the-clock bombing effort except where weather conditions prevented operations.
The Pointblank directive initiated the primary portion of the Allied Combined Bomber Offensive intended to cripple or destroy the German aircraft fighter strength, thus drawing it away from frontline operations and ensuring it would not be an obstacle to the invasion of Northwest Europe. The directive issued on 14 June 1943 ordered RAF Bomber Command and the U.S. Eighth Air Force to bomb specific targets such as aircraft factories; the order was confirmed at the Quebec Conference, 1943.
Up to that point the Royal Air Force and United States Army Air Forces had mostly been attacking German industry in their own way – the British by broad night attacks on industrial areas and the US in "precision attacks" on specific targets. The operational execution of the directive was left to the commanders of the forces and as such even after the directive the British continued in night attacks on the majority of the attacks on German fighter production.
Casablanca directive
Both the British and the US had drawn up their plans for attacking the Axis powers.The British Ministry of Economic Warfare published the Bombers' Baedeker in 1942 that identified the "bottleneck" German industries of oil, communications, and ball bearings; a second edition followed in 1944. At the January 1943 Casablanca Conference the Combined Chiefs of Staff agreed to conduct the "Bomber Offensive from the United Kingdom" and the British Air Ministry issued the Casablanca directive on 4 February with the object of:
After initiating the preparation of a U.S. targeting plan on December 9, 1942; on March 24, 1943, General "Hap" Arnold, the USAAF Commander requested target information from the British, and the "Report of Committee of Operations Analysts" was submitted to Arnold on March 8, 1943 and then to the Eighth Air Force commander as well as the British Air Ministry, the MEW and the Royal Air Force commander. The COA report recommended 18 operations during each three-month phase German submarine construction yards and bases, 2) German aircraft industry, 3) ball bearing manufacture, 4) oil production, 5) synthetic rubber and tires, and 6) military transport vehicle production. Using the COA report and information from the MEW, in April 1943 an Anglo-American committee under Lieutenant General Ira C. Eaker; led by Brigadier General Haywood S. Hansell, Jr.; and including Brig. Gen. Orvil A. Anderson completed a plan for the "Combined Bomber Offensive from the United Kingdom", which projected the US bomber strength for the four phases through to 31 March 1944. Eaker added a summary and final changes, such as:
CBO Plan
A committee under Eaker, led by Hansell and including Brig. Gen. Orvil A. Anderson, drew up a plan for Combined Bomber Operations. Finished in April 1943, the plan recommended 18 operations during each three-month phase against 76 specific targets. The plan also projected the US bomber strength for the four phases through 31 March 1944.Eaker's "Combined Bomber Offensive Plan" was "a document devised to help Arnold get more planes and men for the 8th Air Force" and not "designed to affect British operations in any substantive way." While the CBO Plan was being developed, the British independently drew up a plan in April 1943 entitled "The Attack on the GAF" which identified German fighter strength as "the most formidable weapon...against our bomber offensive" and advocated attacks on airfields and aircraft factories, The document recommended attacks on 34 airfields that were within range of the Rhubarb and Circus operations. The plan identified ten towns as suitable for attack by high level daytime bombing followed by RAF night attacks and may have influenced target selection by the Eighth AF. The Combined Chiefs of Staff approved the "Eaker Plan" on May 19, 1943, and identified six specific "target systems" such as the German aircraft industry :
| 1942 December 9 onwards | US Committee of Operations Analysts |
| 1943 | Combined Operational Planning Committee |
| 1943 July 21 | Joint Crossbow Target Priorities Committee |
| 1944 July 7 | Joint Oil Targets Committee |
| 1944 October | Combined Strategic Targets Committee |
Pointblank directive (PBD)
On 14 June 1943, the Combined Chiefs of Staff issued the Pointblank directive which modified the February 1943 Casablanca directive. Along with the single-engine fighters of the CBO plan, the highest priority Pointblank targets were the fighter aircraft factories since the Western Allied invasion of France could not take place without fighter superiority. In August 1943, the Quebec Conference upheld this change of priorities.Among the factories listed were the Regensburg Messerschmitt factory, the Schweinfurter Kugellagerwerke ball-bearing and the Wiener Neustädter ''Flugzeugwerke'' which produced Bf 109 fighters.
Beginning of operations
The Combined Bomber Offensive began on 10 June 1943 during the British bombing campaign against German industry in the Ruhr area known as the "Battle of the Ruhr". Pointblank operations against the "intermediate objective" began on 14 June, and the "Effects of Bombing Offensive on German War Effort" by the Joint Intelligence Subcommittee was issued 22 July 1943.The Germans built large-scale night-time decoys like the Krupp decoy site which was a German decoy-site of the Krupp steel works in Essen. During World War II, it was designed to divert Allied airstrikes from the actual production site of the arms factory.
Losses during the first months of Pointblank operations and lower-than-planned U.S. bomber production resulted in Chief of the Air Staff Sir Charles Portal complaining about the 3-month CBO delay at the Cairo Conference, where the British refused a U.S. request to place the CBO under a "single Allied strategic air commander," as they did not want to interfere with, nor be part of, a decision they deemed unwise and purely of American military origin. After Arnold submitted the October 9, 1943 "Plan to Assure the Most Effective Exploitation of the Combined Bomber Offensive" on October 22 the "Allied Joint Chiefs of Staff" signed orders to raid "the aircraft industries in the southern Germany and Austria regions".
July 1943 was the first time that the USAAF would coordinate a raid on the same location as the RAF. They were to fly two daylight missions against industrial targets in Hamburg following the opening raid of the RAF campaign against Hamburg. However fires started by the night's bombing obscured the targets and the USAAF "were not keen to follow immediately on the heels of RAF raids in the future because of the smoke problem".
In October 1943 Air Chief Marshal Arthur Harris, C-in-C of RAF Bomber Command writing to his superior urged the British government to be honest to the public regarding the purpose of the bombing campaign and openly announce that:
On February 13, 1944, the CCS issued a new plan for the "Bomber Offensive", which no longer included German morale in the objective: "The subject of morale had been dropped and gave me a wide range of choice.... the new instructions therefore made no difference" to RAF Bomber Command operations. The February 13 plan was given the code name Argument, and after the weather became favorable on February 19, Argument operations were conducted during "Big Week". Harris claimed the Argument plan was not "a reasonable operation of war", and the Air Staff had to order Harris to bomb the Pointblank targets at Schweinfurt.
In practice the USAAF bombers made large scale daylight attacks on factories involved in the production of fighter aircraft. The Luftwaffe was forced into defending against these raids, and its fighters were drawn into battle with the bombers and their escorts.
Pointblank operations
Following the heavy losses of "Black Thursday", the USAAF discontinued strikes deep into Germany until an escort was introduced that could follow the bombers to and from their targets. In 1944, the USAAF bombers—now escorted by Republic P-47 Thunderbolts and North American P-51 Mustangs—renewed their operation. Eaker gave the order to "Destroy the enemy air force wherever you find them, in the air, on the ground and in the factories."Eaker was replaced at the start of 1944 as 8th Air Force commander by then-Major General Jimmy Doolittle Doolittle's major influence on the European air war occurred in early 1944 when he changed USAAF policy which required escorting fighters to remain with the bombers at all times. With his permission, some of the American fighters on bomber escort missions would fly further ahead of the bombers' combat box formations with the intention of "clearing the skies" of any Luftwaffe fighter opposition heading towards the formations. This greater freedom for the fighters inflicted heavy losses on the less maneuverable Zerstörergeschwader of twin-engined heavy fighters and their replacement, single-engined Sturmgruppen of heavily armed and armored Fw 190s, clearing each force of bomber destroyers from Germany's skies throughout early 1944. After the bombers had hit their targets, the USAAF fighters were then free to strafe German airfields and transport infrastructure when returning to base, contributing significantly to the achievement of air superiority by Allied air forces over Europe.