The boss of Belfast City Airport has said the business is still "resilient" despite a question mark over its future in company accounts.
But chief executive Brian Ambrose said the airport had to come up with a new business plan to get through the pandemic - which is reviewed with its banks every month.
And it will have to secure a new agreement next year to protect it from onerous financial conditions known as covenants.
He said he thinks the airport will operate at best on about one-third of usual levels between now and the end of next March.
It went from 100 flights a day to just one after the collapse of regional airline Flybe, which operated 12 routes, followed swiftly by the onset of Covid-19 and the cessation of most air travel.
Latest figures from the Civil Aviation Authority show that just 30,243 passengers used the airport in August. That's down 88.8% on August 2019.
However, almost all the routes left by Flybe's collapse have now been filled by airlines including Loganair, Eastern Airways and Aer Lingus Regional, which Mr Ambrose says boosts its chances of securing future support.
He said a presentation shown to bank bosses every month features an image of the departures board at the airport reflecting its growth in routes.
Mr Ambrose added: "At the worst point we were losing £1m a month, but in the plan we've agreed with the banks and the lenders we're eating into some of the cash, but at that, we believe even without any material pick-up in business, the business is still resilient through the end of that year.
"Our assumption is that we will have a subdued winter and that things will start to pick up again in the spring."
Business demand is being hit by the continued trend for working from home, he said, and even with the majority of routes now filled by new operators, the airport remains loss-making.
He and other airport directors state in company accounts that there is "a material uncertainty" around the business as it battles with Covid-19 and the fallout from Flybe. Mr Ambrose told the Belfast Telegraph that stating a material uncertainty was "unprecedented".
The accounts state that because the bank covenant has to be reviewed again in June next year, "therefore, a material uncertainty exists which may cast significant doubt in respect of the company's ability to continue as a going concern".
The company's 2019 accounts show a loss of £427,000, even ahead of the pandemic and collapse of Flybe.
Mr Ambrose said he has had to renegotiate terms with the banks to obtain a holiday from its covenants, requiring the airport's income to be in a certain ratio to its debt.
A waiver of the terms has been given for June and December this year, and he said he is hopeful it will be granted another in June next year.
"I don't want to presume anything but I think if they were willing to give us a waiver at the time on the basis of what we said we believed we could do, I think we're in a very strong position and have done everything we set out, and there's every reason they would have confidence to extend it, and that will happen at the appropriate point," he explained.
But Mr Ambrose said that when flights were reduced during lockdown "the business isn't actually viable and we're in breach of our bank covenants, so the first thing we had to do is get the banks and lenders on board that we had a viable business".
"On that basis they waived the covenants for a period of time and introduced a fresh covenant with which we're compliant, but as directors of the company we do need to make a statement on going concern in the current environment," he added.
He said the arrival of new airlines had vindicated his confidence. "The only bits we haven't filled is a summer schedule to Newquay in Cornwall, which is really immaterial as far as volumes are concerned, and Cardiff, which we believe we will restart and make an announcement on that," he said.
"My personal expectation is that I think that conditions, short of a vaccine being found, are likely to prevail right through this winter so I think the period between now and the start of October and end of March next year is likely to be about a third of what we experienced of 2019."
While operating profits were £3m during 2019 - down 8% - the pre-tax loss of £427,000 was more than double the £166,000 of 2018.
Mr Ambrose said the "modest" loss was down to expenditure on items such as IT, and its dependence on Flybe, which had been struggling throughout 2019.