Further subsidies are likely to be required for Northern Ireland's three airports as they face losses of about £100,000 a day and struggle to adjust to new pressures following Covid-19, it has been warned.
Belfast City Airport chief Brian Ambrose said he was looking at further safety measures in the airport after pictures of an Aer Lingus flight from Belfast to London on Monday showed passengers sitting closely together without social distancing.
While Belfast City and City of Derry Airport last week received government funding of £5.7m to maintain their daily routes to London, Mr Ambrose has said Belfast City is losing hundreds of thousands of pounds a month with its other flights grounded and revenue streams, such as coffee shops, also closed off.
Graham Keddie, the chief executive of Belfast International Airport, has said it is facing daily losses of £60,000.
City of Derry Airport has been loss-making for some time and is owned by Derry City and Strabane Council, who also gained a £7m bailout from the Executive in 2016.
A spokeswoman said: "The airport will continue to work with governments seeking support for the continued operation going forward." While passenger flights have been grounded at Belfast International, it has continued freight flights overnight.
Dr Esmond Birnie of the Ulster University Economic Policy Centre said the industry worldwide was facing an even tougher challenge than 9/11, with recovery to 2019 levels not likely until 2023, according to consultants McKinsey.
He said airlines will struggle to maintain social distancing.
"It is very unclear how safe social distancing can be achieved in relatively narrow-body planes - even if alternate seats are left empty, especially given the issue of how the air is recycled through the aircraft," he admitted.
"For sure passenger load factors are going to have to be held at a low level which makes it even less likely that routes will be profitable. Further subsidies over and above the recently announced package are likely to be necessary."
Speaking to Radio Ulster's Nolan Show on Tuesday morning, Mr Ambrose said that airport daily traffic had gone from "9,000 or 10,000" people a day to "100 or 200".
He said the Aer Lingus flight had been carrying 154 people on a 174-seat craft after weeks of being just 20% to 30% full.
He said there were "pinch points" - such as where people repack possessions after passing through security - where social distancing had proved difficult to maintain.
But he revealed the airport's operations director was looking into how to lay out the area to maintain social distancing.
Mr Ambrose said the airport, in common with others, would continue losing money in the short term but that it was being supported by 3i, which manages the two pension funds which own the airport.
Asked if monthly losses were in the hundreds of thousands, he said: "Oh, absolutely, it's a serious sum of money."
Mr Keddie said: "When we start flying passengers again, we'll put things in place and work with airlines and regulatory authorities to ensure we have a very healthy and safe operation."
A spokeswoman for City of Derry Airport said "it has put into place all Public Health guidelines at the facility including signage and floor markings, and the majority of passengers currently using the airport are essential workers, who are very cooperative in adhering to the guidelines".