Ryanair could be returning to Belfast next year - with a new home at Belfast International Airport.
Speculation about the move has been growing since new take-off and landing slots became available at London's Gatwick Airport.
The British Airways owner, IAG, has been forced to give up the lucrative slots following its takeover of Aer Lingus, and Ryanair has been trying to acquire them, bidding against other airlines.
Aer Lingus will stop flying from Belfast City Airport to Gatwick on March 26. Passengers booked to fly on the route after that date will be offered transfers to either the Belfast City to Heathrow flight, the Dublin to Gatwick flight or a full refund.
The company issued a statement in which it apologised to customers and said it would contact those with bookings in the coming days.
Industry sources say there's a "strong likelihood" that Ryanair will secure at least some of the Aer Lingus slots and will run a Gatwick service from Belfast International, in competition with easyJet on that route.
A Ryanair spokesman said: "As we have stated, should we secure workable Belfast-Gatwick slots, then we will launch a high frequency service, but we have had no confirmation to date."
Ryanair has made no secret of its desire to return. Chief marketing officer Kenny Jacobs said the airline was in "discussions with both airports with a view to operating flights to and from Belfast in the future". He added: "Ryanair is always interested in new routes. There is huge demand for Ryanair from customers in Northern Ireland who already travel with us from Dublin."
A spokesman for Belfast International Airport refused to comment on the speculation about Ryanair, but added: "We talk to a range of airlines on an ongoing and frequent basis. The International Airport had a 22% growth in passengers in October, compared to the previous year, and there will be an extra 300,000 seats available in the winter flight programme. Our numbers are continuing to grow, and we're approaching a total of 4.5m passengers per year."
Ryanair ceased flights from Belfast City Airport in 2010 following delays to a planned runway extension. It wanted a longer runway so that it could operate flights to a number of European destinations.