BA has been hit by higher fuel costs
A mass meeting of more than 2,000 British Airways cabin crew workers has rejected the airline's plans to reduce costs by cutting jobs and freezing pay.
Staff said they were not prepared to accept an "assault" on their pay, terms and conditions.
Conciliation service Acas will chair a meeting between BA and unions on Wednesday to try to reach an agreement.
BA has been striving to cut costs in the recession. In May, the airline reported a record annual loss of £401m.
The company had set a deadline of 30 June to reach a deal on about 3,500 job cuts, a pay freeze and other changes, but no agreement was made.
At the meeting, workers rejected BA's proposals and instead backed a union plan, which officials said could save between £100m and £130m.
The union Unite said it was prepared to consider a two-year freeze on pay.
Unite claimed BA wanted to introduce a new "starter rate" of £11,000, but said this would lead to a two-tier workforce.
Last month, BA said 800 workers had volunteered to work for nothing for up to a month.
The airline had written to its 40,000 staff in the UK, asking for volunteers to work for nothing to help make savings.
BA chief Willie Walsh has already agreed to work unpaid in July, forgoing his month's salary of £61,000.
A Unite spokesman said: "Our members have shown that feelings are running very high. They have sent a very clear message that they don't want us to make any further concessions that would lead to an assault on their terms and conditions."
Unite said it was not threatening industrial action ahead of Wednesday's talks.
However, if those talks break down, unions could ballot their members on industrial action.
BA workers went on strike in 2003 over terms and conditions, and again in 2005 in a row over catering staff.
The former BA executive Derek Jewson told the BBC there would be no immediate industrial action.
"It won't happen over the next few weeks or months. Acas are involved, and they will try to delay that," he said.
"I would say those who've booked their summer holidays - my view is they're okay. If they can't get it through, the likely date would be early autumn."