There never was a positive kill ratio for the NVA indeed. The best they could get was one downed US aircraft for every 3-4 of their own.
The illusion of a positive kill ration for the communists can only be achieved by counting ALL
US and South Vietnamese losses against all NVA losses (so including the far larger number of US/South Vietnamese losses due to ground fire).
As to Kitty Hawk being "surprised". I highly doubt that.
Her air defense network would have detected the Soviet/Russian aircraft 100nm away or more (depending on the systems in operation). If the people on deck were surprised it was because they weren't warned about it coming in AND because any overflight of a military ship by aircraft from another nation without prior permission is a terrible breach of the protocol used between aircraft and ships on the high sees and therefore unexpected.
I've also heard rumors that the F-22 Raptor could be detected by Russian-built radars.
ANY aircraft can be detected, the F-22 included. Just get close enough to the radar and it will get a return.
Question is, how close does it need to get for the radar to see it? If the F-22 can get close enough to kill the radar before the operator can call in reinforcements or use his own defenses that's enough for the F-22 to complete its mission.
Likewise with the B-2. With the bombbay doors open it can be detected from directly underneath. But when it has the doors open when it's directly overhead of you you're likely to get a 2000 pound bomb on your head in a few seconds so you have other things on your mind than taking potshots at it.