So, you don't see that gliding squirrels are a species in between regular squirrels and what will eventually be true flying squirrels?
Um, no. It's entertaining enough reading just-so stories about how such and such species "almost certainly" evolved from some other species, based in part of common skeletal arrangements, but based in larger part on the need of the Darwinians for it to be so. But to argue that something is going to evolve into something else, when you have no idea about the future selective pressures, population dynamics, genetic mutations, etc., is taking things a bit far.
I know Darwinism is all about blind faith, but that seems to me a bit much even for you guys.