Ryanair has confirmed that it plans to withdraw its operations from Belfast International Airport at the end of October.
Seasonal routes operated by the airline from Belfast City Airport are also due to cease at the end of the summer, meaning that Ryanair will have no services running to or from Northern Ireland from the winter onwards.
The airline blamed air passenger duties and a lack of incentives from both airports for its decision.
"Due to the UK Government's refusal to suspend or reduce air passenger duty, and the lack of Covid recovery incentives from both Belfast airports, this winter Ryanair will cease operations from Belfast International and Belfast City Airport from the end of the Summer schedule in October and these aircraft will be reallocated to lower cost airports elsewhere in the UK and Europe for the Winter schedule which starts in November," it said.
A spokesman for Belfast International Airport said it was disappointing that Ryanair had decided to withdraw operations from the entire Northern Ireland market, having had a presence in all three local airports in recent years.
"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," the spokesman said.
People from the Republic of Ireland who are travelling abroad regularly use the airports in Northern Ireland to do so, including on flights provided by Ryanair.
Currently Ryanair serves Alicante, Malaga, Krakow, Warsaw, Gdansk and Milan from Belfast International Airport.
Malaga will continue to be served by easyJet, Jet2 and TUI, Alicante remains served by easyJet and Jet2 and easyJet will continue to fly to and from Krakow.
The airport has been performing strongly as post-lockdown travel restrictions eased and was the highest performing domestic airport in the UK in June, according to figures from the Civil Aviation Authority.
"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," the airport spokesman said.
"To this end we hope to be able to make announcements regarding fresh route development in the near future."
It is understood that the airport is confident of back-filling many of the routes being vacated by Ryanair.
Separately, Ryanair is expected to end its summer routes from Belfast City Airport next month.
The airline currently flies between the airport and Alicante, Barcelona, Faro, Ibiza, Mallorca, Malaga, Milan and Valencia.
Earlier, Ryanair group chief executive Michael O'Leary said the airline was on track to hit upgraded guidance on passenger numbers, carrying more than ten million people this month as a post-pandemic recovery continues with strong bookings to the end of the year.