Originally Posted by
flyer555
For this specific routing I'd do BA on the SFO -> LHR routes and AA SFO -> LA or LA -> NY, perhaps crediting all into AA if you like straightforward redemption approach inside the US.
But out of SFO AA is weak overall, so if you travel for business from the Bay Area you may need to look elsewhere.
Just be advised that redeeming on BA for a TATL in coach is rarely a good idea, as the fuel charges may well be $600 or more round trip, even if redeeming with AA miles. A business class or higher redemption is still a good value, but you're still going to be out of pocket some cash. If you redeem on AA, you won't pay fuel charges, but the availability isn't as good.