Low-cost airline Norwegian has announced it is beginning transatlantic flights from Dublin, Cork and Shannon to the US from July.
The airline will launch 19 weekly flights from Ireland serving the US east coast.
In a statement, it said the US airports offer good access into Boston, New York and New England.
Stewart International in New York state is 90 minutes with train and bus routes into New York City.
The other airports are TF Green Airport in Providence, Rhode Island, and Bradley International Airport in Hartford, Connecticut.
The airline says introductory fares will start at €69.
American carriers have for years protested Norwegian Air's presence in the US market, complaining that Europe's third-largest budget airline is adding flights that exceed traveller demand, pushing down fares and hurting airlines' revenue.
The carrier is taking advantage of an agreement to liberalise air travel between the United States and the European Union, updated in 2011, which allows airlines from non-EU states Norway and Iceland to fly anywhere between the two blocs.
To keep costs low, Norwegian Air will fly from smaller US airports with lower fees.
Other carriers, including Iceland's Wow Air and Lufthansa's budget subsidiary Eurowings, also offer low-cost long-haul flights.
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Meanwhile Labour TD Alan Kelly has called for an investigation into what went behind today's announcement from Norwegian Airlines and said the new routes were originally sold as a "game changer" for Cork Airport.
He questioned if this was not a "Trojan horse" to get a third terminal opened at Dublin Airport.
. @alankellylabour calls for investigation into 'Trojan Horse' Cork @fly_Norwegian Airlines flights announcement @rtenews pic.twitter.com/XfF9ycrpcm
— Conor McMorrow (@ConorMcMorrow) February 23, 2017
Speaking at the Public Accounts Committee, Mr Kelly asked: "What I want to know is when did the department first know that there were flights going to be out of Dublin?"
He added: "I welcome bringing in Norwegian Airlines, however the way in which this was done needs to be looked at and investigated. We need to get to the bottom of what was really going on here."
Secretary General at the Department of Transport Graham Doyle said he first heard in the last few weeks that there would be flights out of Dublin.
A spokesperson for DAA, which operates Dublin and Cork airports, said it has a statutory responsibility to grow traffic at its airports for the benefit of the Irish economy.
"DAA is delighted that Norwegian has today announced plans to launch new transatlantic routes from Dublin and Cork airports in July. This is a great day for Cork Airport and for Dublin Airport. These new routes will grow Irish tourism and trade and deliver economic benefits throughout the country.
"Management at Cork Airport, supported by DAA, has worked tirelessly with Norwegian to secure this new service and today after a 56-year wait, Cork is now a transatlantic airport," the spokesperson added.
