IAG, owner of British Airways and Spanish carrier Iberia, said Monday it would slash the group's flight capacity by 75% during April and May owing to the coronavirus outbreak.
"For April and May, the Group plans to reduce capacity by at least 75% compared to the same period in 2019," it said in a statement.
Air France also said Monday it would slash flight capacity by 70% to 90% over the next two months due to the coronavirus outbreak.
Capacity could be cut "by 70% to 90%," Air France said in a statement, adding that as a result it expected its financial situation to be "badly impacted" compared with previous forecasts.
Separately, British no-frills airline EasyJet said it may have to ground "the majority" of its fleet over COVID-19, warning there was no guarantee European airlines would survive a long-lasting freeze in air travel.
As part of its drastic action, IAG said it was "cutting non-essential and non-cyber related IT spend, freezing recruitment and discretionary spending, implementing voluntary leave options, temporarily suspending employment contracts and reducing working hours".
IAG added that a management shake-up had been put on hold, noting that Willie Walsh would remain as chief executive.
Walsh had been due to step down on March 26, to be replaced by Iberia CEO Luis Gallego.
"As we respond to COVID-19, Willie, Luis and the board of IAG have decided that management stability across the Group should be a priority in the near term," said IAG chairman Antonio Vazquez.
"We are grateful that Willie has agreed to delay his retirement for a short period at this challenging time," he added.
EasyJet CEO Johan Lundgren meanwhile said that "coordinated government backing will be required to ensure the industry survives and is able to continue to operate when the crisis is over."