Joe Curry, don't forget that the runways at both Turnhouse and Abbotsinch are too short for MTOW ops of long haul aircraft - this means that they can get to New York but as some of the charter boys flying into SFB have found, a tech stop in BGR or similar is required.
Only PIK has a runway long enough for non-stop long haul operations.
Nor can EDI or GLA can extend their runways, either!