While its up here, I don't think you can do it with XML. I'm sure you could do it with Python, but don't know how. This forum is for people asking questions and getting them answered by other people who are here because they have questions. Maybe you should post in the Mod Component Request thread.
I miss the airbase improvement from Civ3 Conquests. However, I also have noticed the problem with only having short range paratroops. I put a National Unit in my Future mod, Long Range Airborne, that has an air range of 24. You only get one, and it requires Advanced Flight. Regular Paratroops I increased the range to 8.