LONDON — British Airways cabin crews will strike over Christmas, their union said yesterday, throwing the plans of thousands of holiday travelers into uncertainty at one of the busiest times of the year.

Strikes are to begin Dec. 22 and run until Jan. 2, said Len McCluskey, the assistant general secretary for Britain's Unite union. McCluskey said 92.5 percent of workers voted in favor of striking.

"You don't often get ballot results like this unless there is a deep-rooted sense of anxiety, concern and anger," McCluskey said at a news conference.

The struggling carrier has announced sweeping changes as part of its bid to cut costs, including cutting 1,700 jobs, freezing pay for current staff and offering lower wages for new employees.

The airline has suffered along with the rest of the industry because of lower demand for travel during the global recession.

Chief Executive Officer Willie Walsh called the action "completely unjustified" and accused unions of misleading cabin crews over the necessity and fairness of the airline's new pay and work proposals.

"It's no secret that British Airways is in financial difficulty. Like other global airlines, we have been hit extremely hard by the slump in business travel brought on by the world recession," Walsh said. "Reducing costs is absolutely essential even to begin heading back toward profitability and long-term survival."

The airline, which is struggling as the global downturn eats away at demand for air travel, has defended the cost-savings measures as necessary to return to profit. The carrier posted a net loss of 208 million pounds ($346 million) for the six months ending in September, its first-ever loss in the period, as revenue fell 13.7 percent.

The union has argued that the changes, introduced in mid-November, have stopped members from doing their jobs properly and were imposed in breach of contracts.

A statement from the British Airlines Stewards and Stewardesses Association, a section of Unite, said its members had been forced into industrial action.

"We are deeply saddened to have reached the point where we must take industrial action to get our voices heard, but feel that we have been left with no other choice," the statement said. "We do not want to cause inconvenience, so even at this late stage we offer an opportunity for disruption not to occur."

McCluskey said the union hoped that the action could still be avoided, noting the decision to strike was difficult.

"We would like passengers to be angry with the company," he said. "It is something of an irony that the people responsible for making BA the best airline in the world are now engaged in a dispute."