Originally Posted by
rapidex
BA are correct. Airport upgrades on AA do not earn extra Avios/Tier Points.
I found this information valuable to help me in booking flights e.g. I have booked to fly in WTP and have chosen to fly on AA metal for the daytime LHR-USA flight but return on BA metal where I might choose an AUP for the overnight return flight. I believe booking on an AA code but onBA metal also means you will not earn extra Avios/TPs if you AUP.