I almost never fly AA and know nothing about the program. I am contemplating flying AA on an international ticket and wondering how AA's international upgrades work. To which fares do they apply? What are their restrictions.

Are any of you familiar with both the AA and UA international upgrade certs? Are they equivalent in terms of use, i.e. would they make an equal trade, one-one?

Any information you can provide would be greatly appreciated.

Thanks, Punki