The "biggest mistake" the Irish Government made in relation to Aer Lingus was retaining its 25.1pc stake in the carrier, according to the chief executive of British Airways owner IAG, Willie Walsh.
Mr Walsh, a former Aer Lingus chief executive, said it makes "no sense" for governments to retain stakes in airlines.
"It's wrong. Governments don't make good shareholders, particularly when you've got to continue to make change," he said, speaking at an international conference in Co Wicklow hosted by the CAPA aviation group.
The Government's stake in Aer Lingus is among the state assets up for sale on foot of Ireland's bailout. But until an outstanding pension issue is resolved, the Government is effectively stymied in its efforts to formally put the holding on the block.
Aer Lingus chief executive Christoph Mueller, speaking at the same conference, conceded that it was never in the best interests of an airline to have a government shareholder.
"We have always said that it's not a long-term solution," he said. He added that this "is the right point in time" for the Government to make an exit but that "it's difficult right now".
"I believe privatisation needs to be privatisation as a whole," said Mr Mueller.
One of the biggest challenges that faces Aer Lingus is ensuring it continues to evolve.
"The big challenge in an airline is to communicate in a way everybody can understand the need for permanent change," he said.
"That's the most difficult thing, because everyone asks, 'Have we done it now'?" He added that change will "never" be over.
"The recession was very good for Aer Lingus," he said. "We have been growing in a shrinking market over the last few years and improved our result year over year, so we have found a business model that can work quite well."
Mr Mueller also said that within the next two weeks he would make a final decision regarding a major investment in a new passenger services IT system for Aer Lingus.
Asked about Ryanair's latest rebuffed attempt to buy Aer Lingus, Mr Mueller said he had no doubts that rebuffing the bid was the right thing to do. Ryanair owns close to 30pc of Aer Lingus.
"If you rerun a movie three times, you easily fall asleep," he said. "I believe Ryanair puts me very well asleep because it's the same show all over again."