It is like Necolatis explained already: if you cannot ship the corresponding module with FlightGear, you would need to ship it with the corresponding aircraft, which involves touching possibly dozens of aircraft.
However, we've had http/xml support for a few years now, so such a module could be loaded via http using the approach detailed at:
http://wiki.flightgear.org/Howto:Making ... from_NasalTechnically, this would mean that people would add 5 lines of Nasal code to their aircraft to load/execute a portion of XML/Nasal code loaded from the official fgdata repository:
Obviously, that would assume that people are online when starting fgfs (which may apply to MP users, but ...)
Otherwise, it would need to be a standalone Nasal file that does not depend on external stuff, including translations and PUI dialogs - which is possible obviously, but I don't quite see many people actually using such a framework. I mean, there only seem to be handful of aircraft using the JA37 approach - so why should we believe that people are suddenly going to adopt such a framework, given that there are so few aircraft doing startup-version checking currently ?