The articles quotes O' Leary as saying that they will offer a premium product as well on board, those flying it may want to avail of a taxi?

AFAIK most coach services out of ISP charge about $30 one way to New York, the train though is a lot cheaper but involves a shuttle/transit connection.

I don't know how we got on to ISP however if I were a low fares airline ISP as a NY destination would make a lot of sense.