As you have probably noticed yourself the your turning ability with the plane is reduced. What you are experiencing is not a bug because your turning ability is reduced when scoped in even when using tank, infantry, towable weapons and so on. That is because the game automaticly lowers your sensibility to allow you to aim better. I believe thi can be changed from the settings menu. Give it a try and take up to the skies once again wingman!
First of all - I'm talking about mouse aim. No, this can't be changed at the moment in the settings. I think you confuse turning rate and turning sensitivity. For new planes and new planes only both turn rate AND sensitivity are reduced. No matter how fast you pull your mouse up - plane won't pitch any faster. What you are saying makes sense only for keyboard input (maybe gamepad).
But even if it's a new "feature" then it should be a toggle, because it messes up muscle memory. Or it should be implemented for all other planes, not just two.
Imagine having different aim down sights sensitivity for your two favorite new weapons that you can't change. Though it can't be applied to infantry, because turn rate is unlimited. But I hope you get the point.
