British Airways has told staff that its Gatwick airport operation may not reopen after the coronavirus pandemic passes.
The admission came in a memo, written by the head of BA's Gatwick hub and seen by BBC News.
BA's Gatwick operation, which is currently suspended, is roughly a fifth as big as its Heathrow hub.
In a separate letter to pilots, BA said it cannot rule out suspending the rest of its Heathrow operation.
In the memo to Gatwick's staff, the company says: "As you know, we suspended our Gatwick flying schedule at the start of April and there is no certainty as to when or if these services can or will return."
In the letter to pilots, BA notes that some of its rivals abroad are facing tough competition. It adds that a quarter of BA's 4,300 pilots are set to lose their jobs.
"We need to ensure that our remaining operation is efficient, flexible and cost-competitive to enable us to survive in an increasingly lean and unpredictable industry," says the letter from senior management.
On Tuesday, BA said it was set to cut up to 12,000 jobs from its 42,000-strong workforce because of a collapse in business due to the Covid-19 lockdown.
The airline's parent company, IAG, said it needed to impose a "restructuring and redundancy programme" until demand for air travel returns to 2019 levels.
The pilots' union Balpa said it was "devastated" and vowed to fight "every single" job cut.
Survival at stake
BA has been flying from Gatwick for decades. Before its merger with BOAC in 1974 to form BA, BEA flew its first routes from the hub in 1950.
Plane-makers and airlines alike have been struggling to cope with the impact of the coronavirus pandemic on their businesses.
On Monday, aerospace giant Airbus announced it was furloughing 3,200 staff at its north Wales site.
Hours earlier, Airbus chief executive Guillaume Faury had warned the company was "bleeding cash at an unprecedented speed".
Mr Faury also told Airbus' 135,000 staff to brace for potentially deep job cuts and warned that its survival was at stake without immediate action.
Meanwhile, US aircraft manufacturer Boeing announced that it would cut 10% of its workforce after it said the lockdown had delivered a "body blow" to the business.
Other airlines, including BA's close rival Virgin Atlantic, have been seeking UK government help.
The aviation industry as a whole has also been lobbying the government for assistance.
On Monday, industry body Airlines UK urged Chancellor Rishi Sunak to extend his job retention scheme beyond June.
It said airlines hit by coronavirus would face "a renewed cash crisis" if the scheme were withdrawn prematurely.