These guys at Qatar, Emirates and EY consider serving the population of the island of Ireland as a total 6.4 million population market.
With volatility of Sterling you probably wouldn't get Euro traffic going North. That coupled with and threat of the UK leaving the EU would leave Qatar running the risk of relying on Northern Ireland's population of 1.8 million to justify a service in its own right. I wouldn't say it adds up. Perhaps the proposal of equalising Corporation tax with the ROI might improve prospects and I hope it does.