Not only that, AA miles cannot be used to travel to the UK from the US on British Airways. Alaska ones can. Since you mention future travel plans of going to the UK, I would suggest using your ~1 million AS miles for some BA F trips, and enjoy the experience, rather than fretting over not having lifetime AA Platinum- BA F is among the best experiences in the air around, and you would be using your AS miles for their best and highest use- redeeming them for tickets with a retail value of many thousands of dollars.