British Airways is to cut almost 600 management jobs by March 2008, the UK airline has announced.
Mr Walsh began work at Aer Lingus as a pilot
The job losses - 35% of the group's 1,715 managerial posts - are the first big move by new chief executive Willie Walsh to cut the firm's costs.
The brunt of the reduction will hit senior management, whose numbers are expected to fall from 414 to 207.
The target date is the one set for BA's move to Heathrow's new Terminal Five, currently under construction.
BA is not ruling out compulsory redundancies to achieve its targets - the first of which, the removal of 94 senior managers, falls due in March 2006.
In October, Mr Walsh said he did not foresee any compulsory redundancies in his shakeups - although BA says that was intended to relate to Terminal Five, rather than the airline as a whole.
The management cuts are intended to provide savings of £50m ($86.3m) as part of an overall target of £300m - the estimated cost of the airline's move to Terminal Five.
In a statement, Mr Walsh - who took over the top job in October after having served as chief of Irish airline Aer Lingus - said he had previously warned that costs were rising in most parts of the business.
"We are restructuring the airline to remove duplication, simplify our core business and provide clearer accountability," he said.
While Mr Walsh was at Aer Lingus, job cuts totalled a third of the airline's workforce.
His predecessor at BA, Rod Eddington, cut the firm's staffing by 14,000 to 46,000 during his five years in charge.