Ryanair's transatlantic flight plan aims for 14 routes
Ryanair could begin transatlantic flights to as many as 14 US cities in the next five years, under a business plan approved by the board of the airline.
Dublin and London Stansted are likely to be among the European hubs through which the new flights will operate.
The airline has begun talks with aircraft manufacturers about long-haul aircraft, a spokesman said.
Ryanair's transatlantic ambitions came closer to reality as Northern Ireland's only air link with the US was restored.
United Airlines had suspended their route between Belfast International Airport and Newark during the quieter period of January to March - but the link was resumed last Wednesday.
Meanwhile, a contract to supply Ryanair with long-haul aircraft is likely to go to either Boeing, its current supplier, of European manufacturer Airbus.
A deal is likely to be hard-fought. Ryanair's most recent contract to buy 200 Boeing jets is worth a staggering $22bn (£14.8bn).
In a statement Ryanair said it would like to offer "low cost" flights to between 12 to 14 European cities and 12 to 14 US destinations.
The plan to operate across the Atlantic was approved by the company's board as part of a wider business plan for future growth at a meeting yesterday.
In the past chief executive Michael O'Leary has made no secret of his ambition to move into the long-haul market.
Yesterday, Ryanair said transatlantic flights are a "logical development in the European market".
Executing the plan depends on access to viable long-haul aircraft, and is estimated by Ryanair to be four to five years away.
If it happens the Irish airline will compete directly with US carrier Delta and the remaining big European players such as IAG-owned British Airways.
Icelandic carrier WOW Air announced its own plans to start selling flights to the US from as little as €149 (£106) earlier this month, but will run an indirect service via Iceland.
Ryanair's decision to set up a US service from scratch comes after its three attempts to buy Aer Lingus have been knocked back by regulators.
Aer Lingus, where Ryanair holds as 29% stake, already flies from Dublin and Shannon to a number of cities in the US and Canada.
If it had been taken over by local rival Ryanair it might have been used as the base for a bigger transatlantic service but the takeover has been resisted by European competition authorities.
Shares in Ryanair closed up slightly yesterday at €10.90 (£7.78) each.