The whole terrorism thing in NI is fast becoming a distant memory TG.
NI is probably safer in that respect than Paris and Americans are still going there in big numbers.
However I would disagree that 'Northern Ireland has a fantastic tourist product...' having visited probably every corner of the land many times over many years (visiting better half's side of the family) I honestly don't think there's much to offer. Belfast is a pretty average large town / small city IMO, Derry is tiny and lifeless and the rest quite boring. Only Enniskillen feels like it has a touristy vibe and the lakes are nice. Thing is though that Enniskillen feels less like NI and more like ROI. There's probably something in that.
A TATL service will rely on the good folk of NI going on holiday but that surely cannot be a subsidised service......low income taxpayers who can never dream of going to the States subsidizing shopping trips to NY for middle class ladies from Holywood.....? Wrong on so many levels.