I am going to the US on AA (V-class) and coming back on BA (V and S class) (fingers crossed as RTN is during strike period). I just signed up to AA Avantage scheme but then saw they don't offer points on BA transatlantic flights and BA reciprocate this. If I were to also sign up to the BA Exec Club can my One World points be amalgamated or is just not worth the effort.

I also flew AA a few months ago, I guess points can't be awarded retrospectively?

Thanks!