BA doing long-haul outside of London is pretty much a never ever. It’s just about within the realms of possibility that AA could decide to give it a go at some point in the future (and we’re talking 5-10 years from now) with a 321XLR to PHL or ORD, banking on connecting traffic to make it work but I wouldn’t bet on it. Continental/United used to do a lot of UK regional flying (back when £1 bought you $2 and New York Christmas shopping trips were very much a thing) and flew from Bristol, Belfast, Newcastle and Glasgow to New York. Now, with the traffic very much originating at the US end, that’s been pared right back in favour of a focus on London and Edinburgh