AER Lingus Regional operator Emerald Airlines is expected to take over at least one of the services at Belfast City Airport vacated by the collapse of Flybe on Saturday.
The Irish carrier, which could also take on some of the 276 Flybe staff made redundant on Saturday, is understood to be preparing to announce flights to East Midlands Airport.
Flybe, which had covered ten routes from Belfast, ceased trading less than ten months after returning to Northern Ireland under new ownership.
It marked the second collapse of the airline in less than three years.
The Federation of Small Businesses (FSB) said latest failure of the regional carrier exposed the fragility of the north’s air links with Britain.
In a letter to the Secretary of State for Northern Ireland on Monday, FSB chair Alan Lowry called on Chris Heaton-Harris and the UK Government to implement recommendations from a 2021 report by Sir Peter Hendy, which said aviation subsidy rules should be revised and the rate of domestic aviation tax cut.
"It is of deep concern that neither of these recommendations has yet been acted upon and that Northern Ireland now finds itself being stripped of a vital carrier that plays such a significant role in our daily connectivity with the rest of the UK and beyond," said Mr Lowry.
Flybe’s latest collapse is not expected to wreak anywhere near the devastation it caused in March 2020.
At that time, Flybe had been responsible for around 80 per cent of flights at Belfast City Airport.
While its new owners Thyme Opco had ambitions of reclaiming anchor status at the airport, it had only been responsible for around 14 per cent of flights up until its weekend collapse.
Of its ten routes from Belfast City, Flybe had been competing head-to-head with Aer Lingus Regional, British Airways and KLM on eight.
But Alan Lowry of the FSB said the lack of competition on those routes raise "obvious concerns around monopoly provision".
Just two airports have been left unserved from Belfast by Flybe’s collapse: East Midlands and Newcastle.
Aer Lingus franchisee Emerald Airlines is understood to be preparing to take on the East Midlands service, while the airport has pointed passengers travelling to the north east of England toward Loganair’s Teesside Airport route.
That’s expected to take its total routes to 11 this summer.
Emerald is actively seeking flight crew to staff its operation at Belfast City Airport,
Meanwhile, Ryanair and EasyJet have also urged the 276 former Flybe employees to apply to work for them.
Ryanair is currently on a recruitment drive at Belfast International Airport, where it is seeking new cabin crew, engineers and mechanics.
The Irish carrier is planning to operate 16 routes from the airport this year, starting in March.
Belfast International has already announced a recruitment event in the hope of filling 300 roles across all areas of its operation, from baggage handling to hospitality.
It expects passenger numbers in 2023 to surpass the record numbers from 2019, when around 6.2 million people passed through the terminal.
As well as the return of Ryanair, EasyJet’s addition of another aircraft to its fleet at the airport, and the launch of Eastern Airways’ new daily service to Southampton, is expected to boost numbers.
It comes as Ryanair reported a hike in fares and profits on Monday, amid strong demand for travel.
The Dublin-based airline said average fares between October and December were 14 per cent above 2019 levels.
It recorded a profit of €211 million (£185m) for the quarter.
That is compared with a €96m euro (£84m) loss a year earlier, and is more than double its €88m (£77m) profit for the same three months in 2019.
The airline carried 38.4 million passengers between October and December, up 24 per cent year-on-year and 7 per cent above pre-virus levels.
Ryanair said there was "strong pent-up travel demand" during the October half-term break and the Christmas and New Year period.
There is "robust demand" for Easter and summer 2023 flights driven by the return of Asian tourists and Americans being encouraged to visit Europe due to the strength of the US dollar, chief executive Michael O'Leary explained.
He recommended that people wanting the lowest fares should book as soon as possible as "we expect these will sell out early".
Ryanair said it has announced 230 new routes for the 12 months to the end of March 2024 and is expanding in Italy, Poland, Ireland and Spain.
The company took delivery of 11 Boeing 737 Gamechanger aircraft in the last quarter, bringing its fleet of the more fuel-efficient aircraft to 84.
Ryanair has said its decision to locate two new Boeing jets at Belfast International represents an investment of around $200 million (£164m).
Meanwhile, Mr O'Leary said an investment of more than $200m (£161m) will save 1.5 per cent of fuel by retrofitting existing aircraft with scimitar winglets.
He added that more than 95 per cent of crews have had pandemic-related pay cuts restored by agreement.
