State airports company DAA said on Wednesday that it had made "significant" efforts to keep Norwegian Air International's Cork-US service through next winter.
The budget airline confirmed that low demand forced it to cancel flights from Cork and Shannon to Providence Rhode Island in the US from November to March.
The news prompted speculation about Norwegian's long-term commitment to Cork Airport, whose only transatlantic service, to Providence, it launched last summer.
DAA, owner of Dublin and Cork airports, said it sought to maximise the benefits for Cork in all its dealings with the Scandinavian-owned airline.
“Alongside management at Cork Airport, DAA has made significant efforts to retain the Cork-Boston Providence service for this winter season,” the State company said.
"Ultimately, airlines make the final decision in relation to how they run their business and which routes they operate and Norwegian has decided to suspend services from Boston Providence to Cork, Shannon and Edinburgh airports for this winter."
The Scandinavian-owned airline began flying between Ireland and the northeastern US last summer, offering seats from €99 one way, something Cork Airport described at the time as a "new chapter" in its history.
Its launch followed a three-year battle with Washington’s department of transportation to get permission to fly to the US.
The Government, individual politicians and business groups supported this with extensive lobbying, much of it focused on Norwegian’s plans to launch Cork Airport’s first transatlantic services.
A Norwegian spokesman said the decision to suspend the winter schedule on the Providence routes was taken following a “comprehensive review” of its services.
He added there was “stronger passenger demand” in the Providence routes over the summer period and flights would continue until October.
Norwegian will continue to assess the routes before confirming its 2019 schedule.
Despite the cancellation of the Providence routes, Norwegian is to expand its Shannon to New York service to four flights per week for the winter period.
"This is an increase of two flights per week over the same season last year and an increase of one flight per week over the current summer 2018 schedule," said Shannon Group managing director Andrew Murphy.
“We are very pleased that the popular New York service has been expanded for this winter and shows the demand for the destination,” Mr Murphy said.
He described the seasonal suspension of the Providence service as disappointing.
DAA pledged to continue working with Cork Airport and Norwegian to boost passenger numbers on the Providence service this summer.
“DAA remains focused on continuing to grow passenger traffic at Dublin and Cork airports for the benefit of the Irish economy and in line with Government policy,” the company said.
Norwegian was interested in launching a Cork-New York service but group chief executive Bjorn Kjos suggested that the airport's runway may be too short to allow this.
Mr Kjos warned last month that Norwegian faced a bigger than-expected first-quarter loss, and said it would raise cash amid higher oil prices and fluctuating currencies.
It said first-quarter pre-tax loss would come in at 2.6 billion Norwegian crowns (€270 million), versus a 1.8 billion crown deficit in the same period last year. Fuel is 12 per cent more expensive than expected so far this year.