this is why (one of the reasons) ff7 is great, ultimate if you will. It's whole story can be interpreted however the player wants to interpret it and it would still be as perfect as omnipotence.

I thought that the Aeris scene was either supposed to be
1. (initial interpretation) Ancients, when they died, went off to some far away magical place and that was her that saved the planet. But that was 4 years ago and i was 10.
2. (recent interpretation) that when Aeris died, like all organisms, returned to the life stream. It was from there that she used her power as an Ancient to manipulate the lifestream and give meteor a rather sore bruise.

But im not saying this is a right or wrong interpretation thats just how i took it.