You have to make each newly equiped squadron a mix of nuggets and experienced aviators. That way you have experienced senior guys later on who started as new guys in a new plane instead of everyone with experience with the new jet getting out of the service and no knowledge getting passed on.
Edit: That was my assumption
Sort of. That's what they shoot for, but inevitably new model squadrons end up being more senior than most. New programs always start out with experienced guys doing the start-up work, and once the fleet squadrons standup, those guys need somewhere to go. Witness MV-22 squadrons with 2 ltcols and 5 majors or more. They still send flight school grads in the usual numbers, but the squadrons still skew senior, which is bad for all--for newbies because there are too many field grade, and for said field grade because there aren't enough "good jobs" to go around.