The head of British Airways said coronavirus was causing an unprecedented crisis for the airline, which is owned by IAG.
Alex Cruz warned that aircraft would be parked like never before and staff laid off, in a hardhitting staff message to address "the worsening situation".
"It is a crisis of global proportions like no other we have known," the BA chief executive told staff in a video message, the transcript of which was seen by Reuters.
"Please do not underestimate the seriousness of this for our company," he added.
The message, headlined "the survival of British Airways", comes as airlines across the world cancel flights and cut costs to counter the plunging demand and US travel restrictions on European passengers.
The industry is braced for further airline failures as no carrier is exempt from the short-term pain that has already seen UK regional player Flybe collapse and Norwegian Air stock lose about 80% of its value in a month.
Cruz said that BA, which along with Iberia and Aer Lingus is part of the financially strong IAG, was more resilient "than ever before" but said that the airline was under "immense pressure".
"We will have to react fast and definitively in response to the worsening situation," he said in the message.
As a result, he said that jobs would be lost "perhaps for a short period, perhaps longer term" and that the company was in discussions with trade unions.
Aircraft would be grounded in a way that the airline has never had to do before, Cruz added.