NCL and UK regions to NYC
The problem here is that for NCL, and for that matter everywhere else apart from LHR and MAN, the chances of sustaining more than a once daily service to New Yorks are pretty slim.
Regional Chambers of Commerce always bang on about what international and long haul connections they want from their local airports, but their members (the companies that make up the chamber memberships) then go off and use their chosen alliances (Star, One World etc) via London, or Manchester, to get the multi daily frequencies and best prices.
New York isn't a good hub; if you want to hub in the USA then Chicago or Atlanta are streets ahead - but even then, as has been said, the hub and spoke opportunities are so much greater in Dubai than they are in the USA, where you can get to pretty well anywhere, provided it's in North America.
Look at BHX for example, bigger market than NCL, but can't even sustain a daily EWR through the winter months. BRS was dropped by United, and Belfast probably only hangs on due to (ex pat. Irish) political pressure and the bribe regarding APD which the rest of UK doesn't benefit from.
My advice - forget about New York; look east, that is where the world's industrial powerhouses are, and before too long, where the principal centre of commerce will be, whether or not the US and EU like it or not.