British Airways said its cabin crew were planning a three-day strike later this month after talks with their union over a new pensions plan and working conditions broke down.
Members of the Transport and General Workers' (T&G) union will walk out January 29-31 and are planning two additional72-hour strikes.
Europe's third-biggest airline said the industrial action would cause "massive disruption for customers and needless damage" to its business.
It urged the union to withdraw its strike threat to help restart negotiations.
T&G Deputy General Secretary Jack Dromey said the union's door remained open for talks, but told BBC television that BA flight attendants had been "pushed too far."
"We want sensible negotiations that solve the immediate problems, but also lead to a fresh start, a new relationship between BA and its workforce," he said.
"But for that to happen the time has come for BA to listen."
Last week, the union said 96 per cent of the cabin crew it represents had voted in favour of strike action over issues that include sick-leave policies and a new pension proposal from the airline.
BA says it will make a one-time contribution of £800 million ($2.3 billion) into the pension fund in return for changes to benefits as part of a plan to lower its £2.1 billion pound deficit to £900 million pounds.
T&G members include 10,500 cabin crew out of a total of about 14,000 at BA.
The airline said it would allow passengers booked to fly with it between January 29 and February 16 to change the date of their trip.
"We are extremely disappointed that the T&G cabin crew union have walked away from negotiations and issued a direct threat to the travel plans of hundreds of thousands of our customers," BA said.
"We remain committed to the search for a peaceful outcome to this dispute and we urge the union to withdraw this totally unjustified strike threat to give negotiations the fullest chance of success," it added.
