'The Sky's the Limit': A Comparative Assessment of the Global Proliferation of Military Airpower in the Early and Late 20th Century

The purpose of this dissertation is to compare and assess the national-level determinants of military airpower diffusion in the early and late 20 th century. To do so I look at the invention of military airpower, its initial adoption patterns, and the intensity of adoption over time. I find that there are two principal determinants of airpower diffusion. The first, and most consistent, determinant is resources, specifically national levels of military power. States with high levels of military capability, as determined by the Composite Index of National Capability (CINC) score, are more likely to adopt airpower earlier and with greater intensity. The second determinant, national status, has had a more complex effect on airpower diffusion. In the early 20th century national status, or a desire to adhere to the norm of technological modernity, increased the speed and intensity with which states adopted airpower. In the late 20th century, though, pressure to acquire airpower capabilities for status purposes no longer held. Instead, it appears that states concerned about their relative levels of status became slightly less likely to pursue airpower. I also find that external threats are an important underlying cause for increasing airpower adoption intensity, that population constraints affected airpower adoption in the late 20th century, and that among the very earliest airpower adopters the presence of public advocacy groups in favor of aviation increased the rate of airpower adoption. In both the early and late 20th century the airpower diffusion process was facilitated by diplomatic communication channels which allowed for the rapid dissemination of information on aircraft performance and capabilities. These findings are synthesized into two proposed models of airpower diffusion in the final chapter. These models are intended to guide future research into military innovation diffusion