Originally Posted by ISTFlyer

Although there is a huge difference between BOS-LHR & PHX-LHR

BOS-LHR is served ( would be served ) by all three alliances and their joint venture partners: AA, BA, DL, UA, VS and JetBlue would be joining them.

On PHX-LHR oneworld is a monopoly and for the forseeable future a BA 787/350 3 or 4 weekly would be able to handle the demand without AA operating this route and deploying a wide-body at PHX.