Originally Posted by wanderlust4life

You always want to book AA flights via AA on their ticket stock and marketed flight numbers. You will have no chance of upgrading an AA operated flight on a QF ticket. If you are able to book a new ticket, then you'd still need to buy 25K miles (since you have no AA miles) plus 350 USD for the upgrade and thats not guaranteed to even clear. Also you can't buy miles for brand new AA accounts due to a waiting period of 30 days so you should make sure to have an AA account anyway. You'd be looking at over 1000 USD just to upgrade an AA flight one way with having to purchase the miles + copay.

And sorry to disappoint you but this isn't an airline like Emirates, Eithad, or British Airways, to name a few, that allow "cheap" upgrades on long-haul flights at the airport check in counter. You will have no chance of doing that on both QF and AA.