Ireland's flag carrier airline is suspending services between Belfast and London's largest airports due to Brexit.
Aer Lingus has announced that it will stop flying between Belfast City Airport - also known as George Best Airport - and Heathrow at the end of the month.
The company's sister airline, British Airways, will start operating three flights a day between the two airports in its place over the winter months.
Aer Lingus will stop flying the route because its Air Operator Certificate (AOC) expires at the end of October, trade union Fórsa claimed.
Because it is an Irish not British carrier, it cannot operate services on UK domestic routes without it following Brexit, Travel Weekly reported.
A UK Civil Aviation Authority spokesperson said that all UK-based airlines had to fly under UK operating licenses after the country left the EU.
Aer Lingus's UK branch had been allowed to fly the route on a wet-leased capacity arrangement from its parent company, the Irish airline, Aer Lingus, the authority said.
The CAA spokesperson said: “We’ve been flexible with Aer Lingus to find a sustainable solution which satisfies both the requirements of the UK-EU Trade and Cooperation Agreement that no longer relies on the wet-leasing arrangements.”
The airline said in a statement: “We are engaging with the relevant authorities in order to allow us to continue to serve this route into the future.
“For the upcoming winter season we will be working with our sister airline, British Airways, to ensure there is continuity of service and no impact to any of our passengers’ journeys.”
The last service from the airline will be on the morning of Sunday, 30 October
Aer Lingus UK staff are likely to be redeployed following the move, meaning potentially significant disruption to their lives.
The flight between London and Belfast takes about one hour 20 minutes, making it by far the quickest and often the cheapest way to travel between the two capitals.
Travelling via rail, road and ferry is a popular route, but often takes longer than ten hours to complete.
Aer Lingus and the CAA have been contacted for further comment.
