Ryanair is to stop flying out of Northern Ireland from the end of October.
The Irish carrier is set to end all flights from Belfast City Airport in September, and from Belfast International Airport by the end of the following month.
The airline says this is due to the UK government's "refusal to suspend or reduce" its air passenger duty, as well as "the lack of COVID recovery incentives from both Belfast airports".
It adds that these aircraft will be re-allocated to lower cost airports elsewhere in the UK and Europe.
A Belfast International Airport spokesperson has described the move as 'disappointing', but that it hopes to be able to provide continuity on routes with other airlines.
"It is disappointing that Ryanair has now decided to withdraw operations from the entire Northern Ireland market at the end of October, having variously had a presence in all three local airports in recent years", the airport says.
"It has been a difficult period for aviation and a time when consumers need some stability and faith in the Northern Ireland air transport network.
"As we have been anticipating such a move, we have been engaging with our existing and other new airlines to provide continuity on the routes to be vacated by Ryanair, and to help sustain employment in the aviation industry at a local level in Northern Ireland."
SDLP economy spokesperson Sinéad McLaughlin says it is a huge blow to the region.
"Today's news will be extremely disappointing to passengers, from commuters to holidaymakers, a lot of people will miss out as a result of these routes no longer being available to people in the North.
"It will also be a blow to both Belfast airports, with Ryanair already pulling out of City of Derry earlier this year.
"We are in the midst of an extremely difficult period for both the aviation and travel industries which have been decimated by the coronavirus pandemic.
"As we emerge from the pandemic I hope to see both sectors rebound - people have been clear, the demand for foreign holidays and travel is there and will need to be met as things return to normal.
She is also appealing to the Stormont Executive to step in.
"Our airports were struggling before the onset of the pandemic and we need to see a proper long-term executive plan to address these issues to ensure our airports remain viable and offer people the best possible choice and experience.
"The first item on their agenda should be finding a new airline or multiple airlines to fill the gap in the market left by Ryanair's withdrawal."