Originally Posted by millionmiler
The rule only applies from London to the US. The BA MAN-JFK flight does earn AA miles when booked as the AA codeshare.
I'm neven seen anyone with a conclusive answer on this one. Obviously coordination of business practice (schedules, fares) historically has required the US goverment exemption to fair trade laws (UA and LH got one), but I suspect the the lack of ability to earn miles and redeem awards is a choice made by AA and BA made as part of their strategy to get such an exemption and also to conveniently protect their own market position.
You can earn AA miles on a BA flight (and vice versa) if it is booked with an AA flight number. So MAN - JFK on BA metal but booked with an AA flight prefix would earn miles. Our Lurker comfirmed this
here