The vast majority of Newcastle passengers on Emirates are not going to end up their journey in Dubai though, likely connecting for another destination in Asia or Africa; like the vast majority on NCL-LHR with BA are not ending their journeys in London, but potentially in the Americas. I suspect the actual sustainable demand just isn’t enough. It’s one thing to fill a plane in the summer or at Christmas, but airlines need those seats filled year-round, especially in the premium cabins, for a route to make financial sense. I can't see a 777 business cabin being filled up on a random Tuesday in February at Newcastle for a direct flight to NYC - not enough business flyers.