Originally Posted by
Wayne Kao
Plat Pro, Platinum, and Gold are upgrade-eligible too but only for certain fare classes.
That indicates that they're upgrade-eligible on all fares. They are upgrade-eligible
at booking if in certain fare classes (and the U space is available); in other fare classes, they become upgrade-eligible close to the travel date (like for all status-based upgrades on AA). This is exactly how it works for AS elites, but the procedure is a bit confusing for those who aren't familiar with it. (It's quite different than AA, which doesn't have these status-based upgrades at booking.)