I believe that it isn't possible, but there have been a number of changes recently. It did always need to be operated by BA.

But with recent changes , for example the GUFs on AA, when on a 125 ticket, maybe they can.

I'm sure someone will be along shortly to tell you exactly what the case is now.

Id be pleasantly surprised if it could be used on AA.

Normally, that generally would mean , they can't....