Leeds USA
I would have thought a LBA to Newark (Nyc) would be a viable route, similar to Bristol with Continental. Leeds is after all at the centre of huge catchment area, greater than all of Scotland. Edinburgh alone has 2 x daily Continental flights at present. Granted Edinburgh draws in a lot of tourist traffic from the States, but I would have thought Leeds would also attract inbound traffic too. We have friends from New York who for the last three years have flown into Heathrow, hired a car, driven through England visiting friends etc and ended up at Edinburgh dropping the car off for no extra charge and flying CO back to Newark. They love it.
Edinburgh is a wealthy city, a financial centre, but so is Leeds and I would think a transatlantic link would work well.