1) It was all a lot harder than pre war ideas believed in just about every area.
2) The main equipment available, the heavy bombers, were locked in by decisions largely taken before any bombing occurred, adjustments could be made but commanders had to make it work with what they were given.
3) No one had flown that many aircraft over those sorts of distances at those sorts of heights, as a result over the first period of the campaign new weather phenomena were being regularly logged. Late war raid on Eastern Germany, bomber route around a pressure system giving them tail winds to and from target.
4) Over the course of the war the air forces expanded the definition of flyable weather but the ability to bomb accurately lagged behind, that resulted in raids to "keep the pressure on" or in the hope for good weather over the target. (Dresden night raid, the cloud cleared over the city while 60 miles away the raid on a refinery was a failure because of thick icing cloud.) Out of 524 forecasts of cloud conditions mentioned in the USSBS 304 were correct, 56 worse, 164 better. On 203 occasions the bombers were sent not expecting to be able to see the target and 126 times when radar would be needed to help visual sighting.
5) Apart from the Luftwaffe reporting its fuel situation the attackers rarely had good intelligence on what short and long term damage raids had done. Even the oil campaign had raids on still knocked out refineries while allowing others weeks of resumed production.
6) Few industrial targets were destroyed, or at least had repairs cancelled.
7) Over the course of the 5 (RAF) and 3 (USAAF) or so years of fighting there were plenty of mistakes, missed opportunities, decisions taken against the evidence and wishful thinking, on all sides.
For details on equipment and methods,
Mighty Eighth War Manual by Roger Freeman
Despatch on War Operations by Arthur Harris
Before deciding what could have been done it is important to know what could actually be done
Day to Day
Bomber Command War Diaries by Middlebrook and Everitt
Mighty Eighth War Diary by Roger Freeman
Fifteenth Air Force War Diary, Bombing by the Numbers by David M Gansz
Carl A. Spaatz and the air war in Europe / Richard G. Davis.
Before writing the book the author compiled a series of spreadsheets of every operation of Bomber Command (summaries in 1940/41 some raids where the bombing became very scattered abbreviated) and 205 Group RAF (from end February 1943) and all 8th, 9th, 12th and 15th Air Force four engined bomber operations. Finding them these days is hard but it is detail no book or report has.
US Official Histories,
UNDER CONSTRUCTION [the planned content is being developed] History of the United States Army Air Force in World War II. Includes HTML versions of various volumes of 'The Army Air Forces in World War II', 'The U.S. Army Air Forces in World War II', 'Wings at War', and 'United States Strategic...
www.ibiblio.org
British operations,
The strategic Air War Against Germany 1939-1945, the official report of the British Bombing Survey Unit. (Think mini USSBS)
STRATEGIC AIR OFFENSIVE AGAINST GERMANY 1939-1945. 4 Volumes by Sir Charles Webster (Author), Noble Frankland (Author)
History at War by Noble Frankland, the story of writing the official history and how public opinion on the history shifted.
The USAAF was largely dependent on non visual bombing aids developed by the British.
There are hundreds to thousands of books on the bomber war. When the USSBS and German records became more available there were a number of books written,. for example.
America's Pursuit of Precision Bombing by McFarland
To Command the Sky by McFarland and Newton
Battle over the Reich by Price
Then comes the writings on subsets of the offensive like,
Target Hitler's Oil by Cooke and Nesbit.
Pre Invasion Bombing Strategy by Rostow
The human experience,
Courage and the Air War by Mark Wells.
Biographies like,
The Quest, Heywood Hansell and American Strategic Bombing in World War II by Charles Griffith
The people involved were trying to predict the future, usually the quickest way to look foolish. So 1941/42 plans for B-29 in service in numbers in 1943 into early 1944, including operations out of Egypt, given where the axis armies were at planning time, requiring any escort to have B-29 range, not B-17 or B-24.
Analysis conclusions range from decisive part of victory to near total waste of effort, to better targets should have been chosen or investment in other weapons would have been better, from the reality of military operations causing casualties to war crimes. Chicken and egg ideas about how to create air superiority and its benefits, lower casualty rates mean an increase in average experience and so effectiveness.
The USAAF started its campaign by assuming the heavy bombers could survive well enough without escorts, that the weather would allow enough accurate visual bombing, that the 500 pound bomb would regularly do lasting damage, that bombing of selected key targets would cripple the enemy war economy or at least very important parts of it. It ended up with lots of escorts, dropping 42% of its bombs on Germany visually, still using mostly 500 pound bombs and bombing the bulk transport links between the various war industries, rather then the factories themselves except for the oil refineries.
The 8th Air force mostly missed the good summer weather in 1942 due to delays in deployment, again missed a lot of opportunities in the 1943 summer due to forces being reassigned to Torch then detachments to the Mediterranean, missed a lot of the summer of 1944 due to Overlord. The many and various calls on the bomber forces to around September 1944 and the time required to create and then be able to sustain the effort meant the mid point for bombs dropped on Germany for the 8th Air Force was mid November 1944, for Bomber Command end September 1944. The tonnage of bombs dropped on oil targets May 1944 to April 1945 by Bomber Command and the 8th Air Force was comparable to the total tonnage of bombs they dropped in 1943. Even in 1945 the pull of other targets existed, 8th Air Force, Richard Davis figures, 211,245.8 tons of bombs dropped, 20,205.1 tons on oil, 118,663 tons on transport, 72,377.1 tons on other targets.
