The government has announced a £5.7m support package to maintain the last two air passenger services operating from Northern Ireland.
The coronavirus crisis has seen all flights suspended, apart from two London services operating from Belfast City and City of Derry airports.
The money will be shared between the airports, Aer Lingus and Loganair.
The package is being jointly funded by the NI Executive and the Westminster government.
Transport Secretary Grant Shapps said: "We must ensure that critical workers can continue to fly over the Irish Sea, and today's investment in these lifeline services guarantees that."
The Loganair flight from Londonderry already receives government support and that will be increased.
The government said the Aer Lingus flight from Belfast City "would be at risk without financial assistance given low passenger numbers".
Secretary of State for Northern Ireland Brandon Lewis said: "The UK Government has promised to do everything in its power to defeat coronavirus and to protect people, jobs and livelihoods across the United Kingdom.
"As part of our efforts, we have been working closely with the Northern Ireland Executive and the Department for the Economy to deliver this new air connectivity support package and we will continue to work closely with them in the weeks and months ahead as we tackle this pandemic."
Steve Frazer, airport manager for City of Derry Airport, said the announcement "provides immediate stability for City of Derry Airport to continue delivering vital connectivity at a critical time for essential workers in support of the fight against Covid-19".
Three phases
Brian Ambrose, chief executive at Belfast City Airport, thanked the politicians who "recognised the strategic importance for the region of keeping Belfast City Airport's links to London open".
"Belfast City Airport will now be able to continue to facilitate a daily service, operated by Aer Lingus, to Heathrow, permitting essential travel for key workers to London," he added.
However, he warned it could take until 2022 for the airport to recover from the coronavirus lockdown.
The airport has seen a dramatic fall in traffic from about 100 flights a day to one flight a day for key workers in construction and medicine.
Mr Ambrose spelled out three phases of reopening the airport: "The next three months is lockdown, very limited activity and preparation for restart.
"Then from August through to next spring, we expect a slow recovery instead of seven flights a day to a single destination, it might be one or two.
"Then heading toward summer next April 2021 but it's probably going to be 2022 before the airport returns to 2019 levels."
Source: BBC