Two major features characterize the historical, sociological, and anthropological studies on aeronautics and space technologies. On the one hand, they tend to analyse aeronautics and aeropace separately as if the two fields were distinct, whereas they have much in common with many techniques moving from one to the other. On the other hand, the prevailing self-referential approach (see Lemonnier, 2004) tends to analyse all social, political, and cultural phenomena as resulting solely from techno-logical innovation. This approach may be useful in that it reveals some details of how these technical systems operate, but it fails to see the whole picture. In this article, we aim to avoid these two pitfals by highlighting both the interconnections between aeronautics and spatial technologies and the way they connect to the economic, political, cultural, and scientific programmes that have been instrumental to their development. This connection is neither natural nor obvious, but rather the result of a socio-historical construct whereby technologies are conceived of as systems. The very distinction between airspace and outer space derives from a cognitive and social construct which at times has contributed to blurring the differences between the fields of aeronautics and space technology. Theodore von Kármán pro-posed to locate the eponymous physical border of the Earth's atmosphere at 100 km (about 62 miles) above the Earth's mean sea level. Although this 'Kármán line' was accepted by aeronautics authorities in the 1950s, particularly by the International Aeronautics Federation, it has neither been universally adopted -the United States determined it to be at 50 miles -nor considered undeniable (Jonathan C. McDowell (2018) for instance placed it at a distance of 80 km), and the issue still causes taxonomical quarrels. Propulsion is the other connection and technical issue linking the two domains that comes to mind. Mastering the right conditions and tools for moving vehicles and machines of varying size and weight whether in the air or outer space has always proved to be a technical challenge, ever since the invention of aircraft and the begin-ning of space travel. The knowledge and techniques of the early 'Aerospatiale' came from the military; this was the case, for instance, for applied mathematics, ballistics, mechanics, and projection as well as research and development on engines, aircraft, and rocket design. The different types of technologies involved in various propulsion systems naturally prompted decades of specific research (on turbo engines, turbo jets, Global History of Techniques, ed. by Guillaume Carnino,