Going all-in with AA early in the tournament isn't a question, but if you're on the bubble, it's worth considering.
In a long tournament, after several hours of play, right before the ITM, one has to consider whether to proudly go all-in with AA and even lose against a lesser hand, or play it safe and fold in hopes of the sure money.
Of course, it depends on the individual, there are those who don't care about the minimum winnings even after several hours of playing, because "I have AA, I go all-in, it will be what it will be."
Personally, I would go for the safe money and not risk it. Of course, only if I can almost certainly pull it out till ITM with my chips.
But in early stages, playing with AA is not a question: going all-in if somebody called all-in before.