Jet2 / JFK
I think Jet2 would do well with a STN-JFK service,
If you look at the JFK flights from STN, Maxjet, Eos and American they all offer a very differant kind of servise, you have Eos with high price business fares, Maxjet with low cost business fares and American Airways with high business fares along with (y) class fares.
The only thing missing is an Airline that offers low cost fares, step up to the plate Jet2, just think of the passengers that would be willing to stop using the above three airlines and start using Jet2 after all price matters.