I know that we cannot do that right now (maybe never), but it would be nice to be able to use a currently active pilot, whose squadron got transferred thus ending his career (example I think is Squadron 245, and another 1 that I cannot remember that I was in and got transferred to Sealand Airbase) in another campaign. Just saying.

This should happen at some point, although even in WOFF, I don't think you can escape a surprise transfer to a nonfunctional squadron or zone...

A required feature i would think. Just a discrete button to enable the player to manually switch is all it would need. Flagging certain airfields or squadrons as active and automatically prompting the player when they are being ' retired' would be better of course, but not critical, just the manual selection would suffice.