In cash games you should never fold AA preflop, but everything else is situational. KK can sometimes be folded, if there is a very solid chance, someone else has AA. I have done it a very few times only. In tournaments an extreme ICM-situation can sometimes make it correct to fold AA, but its very rare, and I have never done it.
A very special situation happened in the TV poker show "big game", where amatour David Fishman was up 130.000 dollars and poised to take an NAPT passport worth another 50.000 dollars.
He was not allowed to leave the game, before 150 hands was played, and choose to fold every hand for the rest of the session including aces. And this made sense. Looking at his whole risk-reward situation it was obviously the right decision for him. And sick enough the hand he folded aces, someone else flopped quads.