Tolwyn became a Light Frigate captain after Action Stations, and we don't know that he ever went back to flying fighters -- he *planned* the McAuliffe/Enyo Engagements as a naval Captain, he did not actually fly the Raptors. (Of course, if you want to get technical, Tolwyn does end up flying again at least once... defending the Tiger's Claw in a Scimitar in 2654).
The various military branches in Wing Commander are quite not equal to the branches today -- there is a lot more dependence on eachother.
Like in reality, both the Space (Air) Force and the Navy fly fighters -- unlike reality, however, both fly fighters off of Naval carriers... something the Air Force today would certainly not do.
You see a lot of transfering between the various services -- Marines to Space Forces, Space Forces to Navy, and so forth... something you definately wouldn't see today.
Pilots recieve their basic flight training and earn their wings before graduation (from the TCSA in Houston (a five year program) in the case of Tolwyn or the TCSNA on Hilthros (a four year program) in the case of Blair and company), and then go to a very short advanced training (on Luna, in the case of TCSA graduates) or flight school on Sirius (in the case of TCSNA graduates). Some cadets then go on to a command school (the Wing Commander Academy).
(Another fun note... there is a Terran Confederation Army, we just never see it).
And stop saying 'Forstchenism'.