British Airways' owner has warned its flights face being grounded for longer with Boris Johnson's travel quarantine plans.
Willie Walsh, chief executive of BA's parent company, International Airlines Group, said the move was "definitely going to make it worse" for the industry, already hit hard by the coronavirus pandemic.
He told MPs the business would now need to review its plans to resume flights from July.
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Speaking to the Commons Transport Select Committee, Mr Walsh also insisted that the plan to shed up to 12,000 jobs at BA was driven by the need to ensure the survival of the airline given the "greatest crisis" ever seen by the sector.
He estimated it could now be as late as 2024 before demand returned to levels before the COVID-19 pandemic.
Mr Walsh was giving evidence to MPs after the prime minister said it would "soon be the time" to bring in a 14-day quarantine period for air passengers to prevent infections from abroad.
Highlighting the "very severe, very significant crisis" facing the industry, Mr Walsh said: "The announcement of a 14-day period (for people) coming into the UK, it's definitely going to make it worse.
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"There's nothing positive in anything that I heard the prime minister say," he added.
"We had been planning to resume - on a pretty significant basis - our flying in July.
"I think we'd have to review that based on what the prime minister said."
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He told MPs that BA's capacity to operate will be "pretty minimal" with an imposed quarantine.
He added: "Despite the fact that there had been some rumours about this quarantine period, I don't think anybody believed that the UK government would actually implement it if they were serious about getting the economy moving again."
Pressed by members of the committee over the job losses, Mr Walsh, whose group also includes Iberia and Aer Lingus, said: "We are not picking on British Airways.
"We're not doing anything that we don't think is absolutely necessary to secure the survival of British Airways and we're doing exactly the same with the other airlines in the group."
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Mr Walsh said: "Our restructuring is solely driven by the fact that we are now in the deepest downturn that the aviation industry has ever seen.
"I don't think I need to hide the scale of it, because it's obvious to everybody. We're not flying our aircraft to transport passengers."
He added: "The industry has changed and anybody who believes that we're going back to the way things were in 2019 misunderstands the scale of the challenge that is being faced."