BA boss Willie Walsh wants all staff to take part in the cost-cutting scheme
British Airways is asking thousands of staff to work for nothing, for up to one month, to help the airline survive.
The appeal, sent by e-mail to more than 30,000 workers in the UK, asks them to volunteer for between one week and one month's unpaid leave, or unpaid work.
BA's chief executive Willie Walsh has already agreed to work unpaid in July, forgoing his month's salary of £61,000.
Last month, BA posted a record annual loss of £401m, partly due to higher fuel bills and other costs.
'Fight for survival'
BA has said that hundreds of staff have responded positively to the request.
But some employees and unions have condemned the plan, saying improvements in the management of the airline were a bigger priority.
Indeed cabin crew and baggage handlers contacted by the BBC rejected the plan out of hand.
"It's a big no. A very big no. Everyone is up in arms. We're not taking it. I'd love to take a month's unpaid leave but I can't afford to do that," said one baggage handler at Heathrow.
But Mr Walsh said BA's drive to save cash was part of a "fight for survival".
"I am looking for every single part of the company to take part in some way in this cash-effective way of helping the company's survival plan," he said.
"It really counts," he added.
BA has been in urgent talks during the past few weeks with trade unions at the company over other ways to save money.
Details of a large pay and productivity deal are expected to be announced on Wednesday.
BA won't say how much it hopes to save by its latest initiative
A company spokesman said it did not have an exact target for the expected savings from its appeal.
"As much as possible, but we don't have a figure," he said.
The idea was first launched last month when the airline asked staff to volunteer for a month's unpaid leave, or to work for free for that time.
That attracted more than 1,000 applicants.
But the company's more recent version of its scheme, launched last week by e-mail and in an article in the internal staff newspaper BA News, is more flexible.
It asks staff to volunteer by the end of this month for between one week and one month of unpaid leave or unpaid work.
The lost salary will be spread over between three and six months.
BA said other airlines, such as Cathay Pacific, had launched similar schemes and a majority of their workforces had signed up for them.
Many employers have imposed pay cuts or short-time working since the recession struck the UK last year.
"In certain cases such as Honda, they shut down for several weeks," said Alistair Hatchett of the research organisation Incomes Data Services.
"Where it is obvious the economic circumstances are tough, people are willing to talk.
"Where employers try it on opportunistically, then there is a challenge," he added.
"While some options may seem unattractive, particularly where they involve reduced income, many employees will conclude that the alternative of losing their job looks bleaker," said Mike Emmott of the Chartered Institute of Personnel and Development (CIPD).