737-8 can make it to Boston. Headwinds could mean a fuelstop enroute as FlyGobespan experienced on occasion from Knock to Boston and New York. Ryanair 737's do not have HF equipped radio and that is expensive to retrofit. Pilots would also need training. O'Leary did say as recently as last month that starting a new airline to undertake TA crossings is still on the cards but Boeing & Airbus prices are not dropping. Both these companies have had significant bookings this year for aircraft.