United Airlines flights between Belfast and New York — the only direct air link between Northern Ireland and the U.S. — will end shortly after the New Year.
The company confirmed in a statement that the last departure from Belfast would be on January 9.
A spokesman said: "We have regretfully taken this decision because of the route's poor financial performance. We will contact customers with bookings for flights beyond those dates to provide refunds and re-accommodate where possible.
"We apologize for any inconvenience caused."
In August, United was offered a £9m rescue deal to prevent the ending of its daily service.
The BBC reports that two-thirds of the money, which was to be given to the airline over three years, was to come from the Northern Ireland Executive.
However, the European Commission has stated that EU rules will not allow public authorities to grant a specific airline an “undue advantage.”
It is understood only part of the aid was ever paid to the company, and that has now been refunded.
I deeply regret United's decision to end its Belfast flight but Executive was absolutely right to try to save it https://t.co/LgdSwmuVsE— Simon Hamilton (@SimonHamilton) November 4, 2016
Simon Hamilton, Northern Ireland’s Economy Minister has expressed regret at the airline’s decision and lashed out at the European Commission, which blocked the funding package.
"The Executive did the right thing with its bid to save this key route. There was a risk to the flight and we stepped in to save it. Faced with the same circumstances again, I would make the same decisions. All public money has been recouped with interest and we retained the route for a longer period, said Hamilton, according to the Belfast Telegraph.
"We were always aware of the potential of an issue around state aid compliance, but given the tight time scale to put a package of support in place, approval by the European Commission could not be sought in advance of agreeing a deal with United and it was our view, on balance, that given this was our only direct flight to the USA, state aid was not a factor.
"It is, therefore, deeply regrettable that unelected bureaucrats in Brussels have effectively scuppered this important flight for Northern Ireland."
Belfast International Airport’s managing director Graham Keddie also expressed outrage at the European Commission saying it “defied logic.”
"You could hardly get a worse example of process-driven madness. To block a support package for an airline that delivers direct access to the United States is almost beyond comprehension,” he said.
"This is a vital link for business and losing it will be a body blow to Executive ministers who use it to promote Northern Ireland to would-be investors from the United States.
"The adverse impact is all the greater, coming as it does ahead of the crucial decision to make Northern Ireland more competitive, with reduced corporation tax designed to stimulate inward investment.
"This is a bad day for the Executive and a bad day for Northern Ireland, which is still finding its feet after a generation lost to conflict."
In a statement, the European Commission said that EU state aid rules would not allow public authorities to "grant a specific airline an undue advantage to the detriment of competing airlines and distorting competition in the single market.”
The statement went on to say that the arrangement between United and the Stormont executive had been put in place "without prior notification" to the commission, which later received a complaint about the deal, leading to the ruling.