Air Lingus offers checked bagage and meals in the example flights below. Norwegian does not. Air Lingus choice of airports close to NYC is a much better choice to Stewart International Airport, which is located 67 miles from Manhattan. Besides that, the transfer into New York is complex, time consuming and more costly so that you in the end saves close to nothing when travelling from Stewart. Click on picture to enlarge!
Observe: This comparison and observation is just valid for the dates shown above. There may well be other flights and dates that is much cheaper when choosing Norwegian. Moreover, the example also validates that it is cheaper to fly into New York State.