These are 'just' graphics, you need to come up with the xml yourself (including stats and the techs they are based on). So they are not a module in their own right (and placing them in one won't make them appear in that mod).
I currently also try to figure out how to integrate some of these in my mod. So I have taken a look around what the other mods do.
Basically there are two options here, either introduce a new tech before Flight (which then leads to Flight) like Early Flight (Varietas Delectat) or Aeronautics (MarnzMod), or simply introduce them with e.g. Physics (requires Rifling and Oil).
As to the strength of these, they range from
Early Bomber : str 8, move 1, cost 100, range 6 (Wolfshanze) to str 12, move 1, cost 120, range 5 (VD)
Early Fighter : str 6, move 1, cost 80, range 4 (Wolfshanze) to str 8, move 1, cost 100, range 4 (VD)
(For comparison : CIV Bomber : 16,1,140,8, CIV Fighter : 12,1,100,6)
Which way you go (either one or a completely different one) is up to you.