Defending auroras early game?

As Aeon, at T1...seems you really badly need air superiority or your opponent will mince your Auroras with T1 bombers.

Is this an absolute requirement, or are there other ways (IE just lots of T1AA)?

In huge quantities then bombers getting one pass are still mass efficient against aurora so t1 aa doesn't help. You're supposed to swap into another tech level to get shields, blazes, and so on while leveraging your more mass efficient tanks in defense. If you want to stay t1 then yeah, win air.