The new head of British Airways has criticised BA staff who went on strike in August, saying their actions had damaged the airline's reputation.
Willie Walsh takes over at BA on Monday
Willie Walsh, who takes over as BA chief executive on Monday, said the wildcat strike by baggage handlers and check-in staff could not be justified.
Hundreds of staff walked out in sympathy with sacked workers at the airline catering firm Gate Gourmet.
Some of BA's working practices were "completely irrelevant", Mr Walsh said.
The former Aer Lingus boss has been acting as BA's chief executive designate since April and will formally succeed Rod Eddington on Monday.
Mr Walsh takes over at a difficult time for BA.
It is one of the world's most profitable airlines but is contending with soaring energy bills and a recent history of fraught industrial relations.
An unofficial strike by BA workers in August severely disrupted services for almost 48 hours and is estimated to have cost the airline up to £40m.
Mr Walsh said the strike action - triggered by an industrial relations dispute at Gate Gourmet - had been highly damaging.
"It was damaging to our reputation, to our brand and to morale and we are going to have to work hard to recover customers who were impacted," Mr Walsh told The Sunday Times Magazine.
Mr Walsh said the strike was unwelcome to the "vast majority" of staff.
"You have to be clear that this was nothing to do with British Airways and I don't believe that anybody can seek to justify it in retrospect or suggest that we should have seen it coming."
BA has been hit by strikes in the past two summers
BA is looking to make savings of £300m by 2007 ahead of its move to the new Terminal 5 at Heathrow a year later.
Unions are worried that Mr Walsh - who transformed Aer Lingus' fortunes after cutting thousands of jobs - could oversee a substantial reduction in the workforce.
"I think that you could say that people are apprehensive and concerned," Pete Sweet, chairman of the BA Trades Union Council, told The Sunday Times Magazine.
Mr Walsh said he would do what was right for BA.
But he warned that some of the airline's existing working practices were incompatible with improving customer satisfaction and safety.
"It is fair to say that there are working practices that are completely irrelevant to the business today.
"That is why Terminal 5 represents an opportunity for us to start all over again."