More than 12,500 BA employees, balloted by trade union Unite in November, voted by a 92.5 percent majority to walk out from December 22 for 12 days, Unite Deputy General Secretary Len McCluskey announced Monday.
In a statement to customers on its Web site, BA said it was reworking its flight schedules for the strike period and would announce them as quickly as possible. It said it would inform affected customers by e-mail or text message.
The strike ballot came after the airline introduced cost-cutting measures including a two-year pay freeze and reducing the numbers of cabin crew members on long-haul flights.
BA says the changes, introduced in the wake of a record pre-tax loss of more than $485 million for the six months from April to September, will save the airline $665 million.
McCluskey warned that the strike would inflict "catastrophic damage" to the airline if it went ahead and urged British Airways bosses to return to the negotiating table. He said union members had been pushed into a corner by BA Chief Executive Willie Walsh.
"We've been saying to Mr. Walsh this seems crazy at a time when British Airways is suffering badly through an economic downturn that he should force us into a dispute that would have catastrophic effects on the economy of the company," McCluskey told CNN following a news conference at Sandown Racecourse, southern England.
"That's why we're hoping that even at this late hour the strength of feeling of our members will get through to the company. We are available 24 hours a day to meet the company. If they are up for getting an agreement I'm confident we can get one."
McCluskey said passengers, upset at having their holiday plans disrupted, should take their anger out on the airline. McCluskey said his members were not "mindless militants" but decent men and women who had been forced into a corner by British Airlines.
But Walsh said strike action was "completely unjustified" and called on union chiefs to resume negotiations. He said the airline had agreed pay cuts with pilots and more efficient ways of working with engineers, while a third of managers had taken voluntary redundancy.
BA cut 1,900 jobs over the summer through reduced overtime, increased part-time working, and voluntary redundancies. But it plans to eliminate 3,000 more jobs by March 2010, Walsh said last month.
"My admiration for the professionalism and skills of British Airways cabin crew is second to none. They are an absolutely vital part of our airline, and a great asset," Walsh said. "But they have been disgracefully misled by Unite as to how our company-wide cost reduction program would affect them."
CNN's Richard Quest said the impact of the potential strike would be devastating for BA and said the consequences would be disruption for BA passengers and higher prices for travelers booking on other airlines.
"Their planes are heaving and they are now about to face a strike," Quest said. "They are going to have tens of thousands of passengers who are concerned, who are worried. I imagine anyone who is going away for Christmas is now thinking about shifting their booking if they can."
A spokesperson for ABTA, which represents travel agencies and tour operators in the UK, said passengers booked onto BA flights should wait and see what contingency plans the airline puts in place and whether the strike goes ahead.
"Hopefully the strike could be called off and if you cancel your flight now then you may not be able to claim a refund," she said.
Unite has called on the High Court to rule on whether BA's cutbacks have breached its member's contracts but the case is not scheduled to be heard until February 2010.