The other potential disadvantage oneworld may have, assuming AA and BA can finally get their act together / get government approval to extend their alliance across the Atlantic, is ease of connections at LHR. Does anyone know if AA and BA (and Qantas and CX and Iberia and other ow carriers for that matter) plan to co-locate at T5? If not, connections will be quite a bit more painful relative to UA-LH at FRA, DL-AF at CDG, and NW-KL at AMS.

Would be ironic given that the other alliances are co-locating at Heathrow (eg SkyTeam at T4, Star at T3?) and oneworld carriers do not have the same benefit! Perhaps LHR needs to build some airside hi-speed train links to facilitate inter-terminal connections, like they have at KUL, FRA, SIN, HKG and other such places.