yeah, I was thinking about the baby theory, but as it will be half water half air, how would that work out???
my theory was that Aang, now a master in energybending, would take some non-bender humans and endow them with air bending power. although I dont see aang just "re-making" the air nomads and may just let it go. Well, until the return of the air avatar there would be let's say 80 years per avatar, although avatar kyoshi lived to be 200, but lets say 80 times three would be over 200 years...there could be time for no-benders to learn air bending, but since the nomads learnt it from the flying bisons, who are now extinct, I dont see that happening.
Hmm, this is puzzling indeed. 