I know it can't be upgraded with miles or miles +cash on AA. In fact, AA agent told me they will likely add upgrades from PE in the future when the flights with PE are more widely available but not yet.
I can upgrade for cash now but it is essentially at the full fare price.
What I would like to be able to do is do some sort of last minute upgrade but I've not seen that on AA in a long time. Wondering if it might be available via Iberia since they do seem to offer last minute upgrades for a fee
AJ