Sean Doyle, the Aer Lingus chief executive and chairman, is to become the new chief executive of British Airways.
In a statement this morning, IAG - which owns both Aer Lingus and British Airways - said that BA chief executive Alex Cruz is to step down from the role. However, he will remain on as the airline's non-executive chairman.
Meanwhile, Donal Moriarty, chief corporate affairs officer at Aer Lingus, will become the airline's interim chief executive.
A permanent appointment will be announced in due course, IAG said.
Sean Doyle worked at British Airways for 20 years before moving to head Aer Lingus nearly two years ago. He will also take over the BA chairman role after a transition period.
IAG also said that Fernando Candela, LEVEL's chief executive, is joining the group's management committee in a new role of chief transformation officer.
Today's changes were announced by IAG's new chief executive Luis Gallego after a month in the job.
"IAG has proved itself to be one of the world's leading airline groups with a portfolio of successful companies," Mr Gallego - who replaced Willie Walsh - said.
"We're navigating the worst crisis faced in our industry and I'm confident these internal promotions will ensure IAG is well placed to emerge in a strong position," he added.
Sean Doyle faces a huge challenge at BA, which like all airlines, is struggling due to low levels of flying during the pandemic.
IAG last month raised €2.74 billion to reduce its debt and help it survive the pandemic.
The last few months have been tough for Alex Cruz who was tasked with driving through 13,000 job cuts at BA, making him a frequent target of trade union hostility.
Gallego, who had been boss of IAG airline Iberia, pipped Cruz to the IAG top job earlier this year, replacing Willie Walsh.
Gallego and Cruz previously worked together at Spanish airline Vueling, now also owned by IAG.
Analysts suggested that a number of high-profile blunders at BA under Cruz, including a data breach for which it was fined $230m in 2019, and an IT failure in 2017 which left tens of thousands of passengers stranded, would not have helped his cause.
Cruz was also at the helm last year when BA pilots went on strike for the first time, costing the airline more than €137m.
Davy analyst Stephen Furlong said it was not a surprise that Gallego had moved quickly to make the changes, calling him "decisive" and noting that his background is of leading significant restructuring at IAG's Iberia Express and Iberia.
"I suspect they wanted a newer face going forward with BA," Furlong said, adding that Doyle had proved himself at Aer Lingus, which went into the coronavirus crisis as IAG's best performing airline.
IAG shares traded were lower in London trade today. Hurt by the pandemic, the stock has lost 75% of its value in the year to date.