Should Stormont be subsidising Belfast-New York flights?

A rescue deal has been agreed to stop the US airline United ending its daily service between Belfast and New York. The assistance is believed to be worth around 9 million pounds over 3 years. Most of the money will come from Stormont. Without the package, United would have stopped flights between Belfast International and Newark from September. The Economy Minister, Simon Hamilton, says the route needs support as it's crucial to the local economy. But is it value for money?