92: So Close Yet So Far


Airpower was an important feature of the First World War, but after the conflict was over it entered into the great unknown - peace.


  • British Intelligence on the German Air Force and Aircraft Industry, 1933-1939 by Wesley K. Wark
  • Case Studies in the Development of Close Air Support Edited by Benjamin Franklin Cooling
  • The Development of the Italian Air Force Prior to World War II by James J. Sadkovich
  • The Strategic Dream: French Air Doctrine in the Inter-War Period, 1919-39 by Robert J. Young
  • History and Evolution of Close Air Support: World War I to the Korean War by Michael J. Chandler
  • The Origins of American Airpower Theory by James R. Cody
  • The Price of Air Power: Technological Change, Industrial Policy, and Military Aircraft Contracts in the Era of British Rearmament, 1935-39 by Sebastian Ritchie
  • Airpower and the Cult of the Offensive: Royal Air Force, 1918-1938 by John R. Carter
  • The Royal Air Force, Air Power and British Foreign Policy, 1932-37 by Malcolm Smith
  • Strategy for Victory: The Development of British Tactical Air Power, 1919-1943 by David Ian Hall
  • The War in the Air 1914-1994 Edited by Alan Stephens
  • Why Air Forces Fail: The Anatomy of Defeat Edited by Robin Higham and Stephen J. Harris
  • The Air Panic of 1935: British Press Opinion between Disarmament and Rearmament by Brett Holman
  • Trenchard and “Morale Bombing”: The Evolution of Royal Air Force Before World War II by Phillip S. Meilinger
  • The Heavy Bomber at its Inception by Jerry Hendrix and James Price
  • Rhetoric and Reality in Air Warfare: The Evolution of British and American Ideas about Strategic Bombing, 1941-1945 by Tami Davis Biddle
  • Incubate Innovation: Aviation Lessons from the Interwar Period by Lieutenant Philip d. Mayer
  • Strategy for Defeat the Luftwaffe 1933-1945 by Williamson Murray
  • Military Innovation in the Interwar Period Edited by Williamson Murray and Allan R. Millett
  • The Paths of Heaven: The Evolution of Airpower Theory by The School of Advanced Airpower Studies


Hello everyone and welcome to History of the Second World War Episode 92 - Interwar Airpower Part 1 - So Close Yet So Far. Before we get started today I wanted to let you know that on June 25th I will be speaking at the Intelligent Speech 2022 conference. This is a fully online event where I will be joined by over 35 other historians and history podcasters to discuss a wide range of topics. I will be giving a talk entitled “The Correct Wrong Choice: The Interwar Years and Results Based Analysis” in which I will chat a bit about how we should approach discussions about events that happen before major events like the Second World War. During the session there will be an opportunity for some Q&A, which was a ton of fun last year. If you register before June 1st you can get the Early Bird special for just $20, and you can use my code Second, that is just the word Second, at checkout so that they know that you heard about it here. You can find the link in the show notes, or you can head over to intelligentspeechconference.com to register or to find out more. Now back to our regularly scheduled programming. Between the period 1914 to 1945 there would be no area of military technology that would advance more than that in the realm of air power. In 1914 the militaries of the world had small numbers of fragile, wooden framed, air machines that were primarily used for reconnaissance. By 1945 there would be jets capable of reaching speeds of 900 kilometers per hour, strategic bombers capable of dropping thousands of kilograms of bombs at targets thousands of kilometers away. And beyond even the technical advancements, which were staggering, air power would take its position as one of the key areas that militaries had to consider and excel in if they wanted to be taken seriously on the global stage. Within the two world wars that serve as bookends to this 1914 to 1945 period, there were massive advancements in both technology and theory. However, our series of episodes that will occupy the next 5 episodes of the podcast will be focused on how those two things evolved over the course of the interwar period. Coming out of the First World War the various air forces that had been involved in the fighting emerged from the war having proven their importance and their power on the battlefield. During the war the more traditional military arms, the armies and the navies, had not been able to bring the conflict to a quick conclusion, and while the air forces of Europe had been equally unable to bring victory, air power advocates could at least point to the immaturity of air power both technologically and theoretically. This provided a lot of space for air power evangelists to try and convince everybody around them that air power was the future, and that it should be pursued with the greatest possible vigor. Just to quote three of those evangelists, as a way of kicking off these episodes. Here is British General Hugh Trenchard, leader of the Royal Air Force after the First World war, speaking in 1916 “It is the opinion of those most competent to judge that the aeroplane, as a weapon of attack, cannot be too highly estimated.” Here is American Colonel William Mitchell, better known as Billy, speaking in 1925, Mitchell being well known for his belief that air power would completely change how war at sea was fought: “Air power, both from a military and economic standpoint, will not only dominate the land but the sea as well.” Finally, here is Italian General Giulio Douhet, one of the leading advocates for strategic bombing, in 1921 “To conquer command of the air means victory; to be beaten in the air means defeat and acceptance of whatever terms the enemy may be pleased to impose.” During this episode we are going to focus on some of the lessons that nations learned from the First World War, and then how some of these lessons were applied to the close air support concept.

The idea of supporting fighting on the ground from airplanes would be developed before the First World War, almost as soon as aircraft began to enter into military service, they started trying to strap guns to them to prove that they could be used as a weapon. Evolution in this direction would be greatly accelerated by the war. In 1914 aircraft were primarily used as observation and scouting platforms, and from that position the earliest kind of support for ground attacks was dropping simple explosives out of the cockpit. From these relatively quaint beginnings the concept and capabilities around close air support would greatly increase as the years went by. By the last 18 months of the war specific tactics and aircraft had been designed to facilitate supporting ground operations from the air. What had developed was the ability of pilots to engage targets on the ground with both machine guns and explosive bombs. There were many differences in the details between the French, German and British implementations of these practices, for example the British favored multi role aircraft while the French and Germans began to develop dedicated ground attack platforms. But they were all achieving the same goals, bringing together the capabilities of air power with the requirements of ground attacks to try and help make those ground attacks successful, in much the same way that artillery was used for the same purpose. These close support tasks were dangerous, both from enemy ground fire, and also from the threat posed by enemy fighter aircraft, but there were also some benefits that offensive operations had at this time. The offensive use of airpower, be it in close support tasks, bombing missions, or air superiority missions always had the benefit of concentration. I will just borrow a description of the problems faced by the defenders from Rhetoric and Reality in Air Warfare: The Evolution of British and American Ideas about Strategic Bombing, 1941-1945 by Tami Davis Biddle “The relationship between defenders needed and attackers faced is sharply nonlinear: defenders require a certain number of aircraft simply to cover the relevant airspace, even if few bombers attack—the requirement is driven more by the area to be defended than the size of the attack. Hence a small attack still requires a relatively large defense to defeat it. But once defenders have deployed enough fighters to make it likely that any given raid will be intercepted, further increases in bomber fleets do not much increase the number of fighters needed to defeat them. All air forces discovered this in the Second World War, but by 1918 none had seen more than small raids, and thus all they had observed were the needs of defending against small attacks, which seemed disproportionate.” These problems for the defenders would not really be solved until radar became more readily available before and during the Second World War.

After the First World War, after over four years of massive expansion and innovation every air service had to find its path forward. For many of them, for example in the French or American militaries, the air service was still under the control of the Army. But in Britain the Royal Air Force had been created before the end of the war. This put the RAF in an interesting position in which it had to justify its existence in a way that was not present in other militaries. It was impossible for any serious military observer to say that air power was not important, but the RAF was faced with the added requirement of convincing others that they needed to be separate from the other services, and that they needed continued funding. The RAF, with Trenchard at its head, would push for the idea that air power could help maintain control of the British Empire, doing basically what the British Army had been doing for generations, only at a cheaper cost. The exact efficacy of these policies and the RAFs actions is out of the scope of this episode, but it is a good example of how air power would push beyond its First World War experiences after 1918. There were many advocates of air power that were trying to find a way to push air power forward in the world of greatly reduced defense budgets and pushing into areas like aerial policing was one of them. Another area would be in the growing belief that strategic bombing would be a critical part of the next war, even though it had played only a very marginal role during the First World War. We will discuss the efforts of those strategic bombing evangelists next episode, but for the rest of this episode we will focus on close air support, an areas where air power had been used for real impact during the First World War, but which would have to grow and evolve just like every other facet of military technology and theory during the interwar years.

As I mentioned earlier, it took some time for close air support to have a meaningful impact on the fighting during the first world war. This impact was felt after many years of slow innovation in how aircraft could be used. But then after the war close air support became a topic that was greatly discussed, if only because the various groups involved had different views of its importance. From the side of the Armies, they considered it to be incredibly important and to be the number one reason that air forces existed. This may have been the views of Army leaders, but aviation leaders had a different view of how their resources should be used. The details were always different from nation to nation, but at a basic level the disagreement was around how closely tied should aviation resources be to the ground actions. On both sides there were selfish reasons that the ground and aviation forces had their own desires around how best air units could be used to support events on the ground. From the side of the ground units, aviation assets were just a way of making their efforts more successful, and the closer the air and ground units worked together the more effective they both would be. For air power advocates, they wanted some level of freedom to decide how best to use their own resources, they did not want to be narrowly focused on the targets that the army demanded. Beyond these more selfish reasons, there were also fundamental disagreements about the best type of targets to hit. For all of their desire for their own freedom, aviation leaders also clearly believed that their air units would be the most effective when provided what was termed indirect support. Indirect support meant supporting ground units, but generally by attacking targets that were disconnected from the immediate fighting. Example of indirect targets might be enemy artillery positions, transportation and concentration areas, communications, and similar targets. There were really good reasons to pursue this type of action, especially during the 1920s and 30s. One challenge was identifying targets on the ground, targets that often did not want to be seen, especially with the ever changing nature of the battlefield. Soviet aviation authority A. Lapchinskii “The further we go into enemy territory the more we can count on very important and immovable targets; and on the other hand, the nearer we are to the battle, the more we will have to count on what is called the ’emptiness of the battlefield’”. But even if a pilot could find the target they were looking for, that just introduced another massive problem, hitting it. It was very difficult to hit targets on the ground from any reasonable height, but anti aircraft fire was very potent, which caused pilots to want to fly quite high. But above 10,000 feet, which is where many pilots wanted to stay, resulted in very low bomb hit rates. For example the Luftwaffe put the percentage of hits from 12,000 feet at less than 2 percent, and that was when trying to hit a target the size of a football field. That is pretty rough, especially when many targets were much smaller. These very real technical challenges were used as reasons for the support of greater freedom of operations for air units, which would be more or less successful based on the nation

Each of those nations would then approach ground attack, and close air support, differently during the 1920s and 1930s. Some would create dedicated units quite early, like the United States in 1921, while others would not devote specific resources to the problem until the 1930s. Budgets were always problematic, and resulted in there never being enough time and money spent on refining the ground attack concepts. For example in the United States the Third Attack Group had been founded in 1921, and contained four dedicated attack squadrons. A few years later 2 of those squadrons were deactivated due to budget cuts. Finding money was just one of many problems that were common in most air forces as they tried to refine ground and air coordination. Another major problem was around how to communicate between the two groups. The technical side of this problem had been solved by the radio, which would be the critical link between ground based units and aircraft in the air. The larger problem was one wrapped around the question of who on the ground was the one calling for air support, and how did they get information from units at the front. The further forward the link to the aircraft was placed on the battlefield, the more timely support could arrive, but the further back it was the greater visibility there would be to action along the entire front, and the greater the ability to concentrate available aviation assets. It was a balancing act that shifted based on available resources, technologies available, and doctrine. For example the French, which set a system where an air support request had to go quite far up the chain of command, had a system where it could take four hours for a request to result in the dispatch of aviation assets. Another difficulty was around properly modeling air to ground operations during peace time exercises. Developing exercises that accurately represented the realities of combat is an entire series of podcast episodes all on its own. But at the basic level it was really challenging for militaries in the 1930s to not just predict what war would be like, but then to develop and execute exercises with peacetime forces that in any way resembled the demands that would be placed upon them in war. Close air support was no different, with many nations not being able to accurately simulate combat operations, which for some nations would result in overly complicated demands being placed on ground control and pilots as they tried to coordinate their attacks. It was very easy for the actual mechanics of the actions between the two forces to become massively overcomplicated, resulted in the system breaking down during the stress of combat. Even with all of these challenges, some nations would put a lot of effort into making their processes work, and there were many who believed that the tasks of supporting ground units would be essential in the future. For example here is a quote from the American Billy Mitchell on the ways in which attack squadrons could be used “During offensives, attack squadrons operate over and in front of the infantry and neutralize the fire of the enemy’s infantry and barrage batteries. On the defensive, the appearance of attack airplanes affords visible proof to heavily engaged troops that Headquarders is maintaining close touch with the front, and its employing all possible auxiliaries to support the fighting troops.”. Mitchell’s quote also touched on another aspect of air support that had been learned during the First World War, morale. There are countless accounts from the war about how air superiority over the battlefield impacted the soldiers on the ground. German soldier on the Somme on July 20th, 1916 ‘Our infantry up front had come gradually to the belief that they had been abandoned. We cried once more and in vain for some help against the aircraft.’

Probably the best known of all of the militaries, at least when it came to close air support, was the Luftwaffe. However, this reputation was actually built without having many dedicated close support squadrons. The Luftwaffe had for much of its existence put most of its focus on what it called indirect support, basically preferring targets close to, but not directly engaged in the fighting. This was reflected in its force structure, with only one dedicated close air support unit at the start of the war, and it was flying the Henschel 123 biplane, not the Ju-87 Stuka which would become synonymous with close air support over the following 2 years. That did not mean that German squadrons could not provide direct support to ground units when required, but there was the belief that focusing on slightly more distant targets would be more impactful to the overall course of a campaign. But they were in no way against working closely when necessary, and over the course of the opening campaigns of the war they would develop the experience and processes to get around many of the problems that were experienced in the prewar years. For a bit more information about the Luftwaffe, refer back to Episode 83, and don’t worry we will be discussing their actions early in the war at great lengthy.

In Britain the relationship between the Army and the Air Force would be, if anything, far more tense than in Germany. The Royal Air Force had made its case that it needed to be a separate service entirely, a separation that was granted during the First World War. It would then spend most of the interwar period trying to maintain as much of that independence as possible. By its very nature close air support missions meant sacrificing that independence, even if only temporarily as units were put under the control of Army officers. This, along with the belief that there were better things for attack aircraft to be doing meant that the RAF put relatively low priority on all close air support tasks. In the years before the war RAF leaders would add the events in China and Spain to their list of arguments as to why this was the best path to pursue. As with any argument about military doctrine during this period they would refer back to the First World War, stating that those who wanted to spread out aviation strength to various army units were forgetting how critical it was to be able to maintain the ability to concentrate resources on a single task. In their view the much more beneficial plan would be for British bombers to try and create an impenetrable ring around the battlefield, to prevent enemy troops from joining the battle. At the same time fighter squadrons would seek to destroy any enemy aircraft that entered the battle zone. While preventing the enemy from interfering with the ground battle, it was also hoped that this would better preserve Royal Air Force strength, with concerns that missions over the battle area would result in an acceptable and unsustainable attrition rate. There were however dedicated units that were responsible for working with the ground troops in what were called cooperation squadrons, but these were primarily designated for reconnaissance and observation purposed. Overall, the resistance of Royal Air Force leaders to really commit to the task of close air support meant that, even if it was a subject that was covered in Royal Air Force regulations, it was not well supported or well thought out. As war grew closer there was increased political pressure to see the Army and RAF work closer together, given the growing commitment of Britain to France and the continent. But there was simply and unbridgeable divide between the two camps. In March 1939 General Wavell would, in his report on recent joint training exercises that they “showed conclusively that the RAF had given little or no thought to the problem of close support of ground operations, that their pilots had not been trained to this form of war, and that the results on the targets pro- vided were extremely poor in consequence … I doubt whether the ex- ercise occasioned even a ripple of thought about close support to pass over the minds of the air staff.” None of these issues had really been resolved when the BEF went to the continent after September 1939. Some amount of air support was provided, with an initial 12 squadrons of bombers and fighters, but they were still clearly not setup or structured in a way that leant itself to easy coordination.