If I can quickly respond, and very briefly, one of the stealth capabilities' big advantages is in more of a battlefield area. They're very important in areas like the Middle East, but in defence of the continent you don't need to be stealthy because you just need to be able to track down your opponent, so NORAD will be able to operate with fifth generation, even fourth generation planes in the air for some time while those capabilities are developed for much more hostile-fire situations where our presence would be more likely to be detected and counterbanded by forces on the ground.
On December 4th, 2014. See this statement in context.