British Airways cabin crew will launch a fresh wave of strikes on Thursday in a long-running dispute over pay.
Members of Unite in the so-called mixed fleet - working on short and long-haul flights - will walk out for three days, following a three-day stoppage which ended on Tuesday.
The two sides have clashed over pay, with Unite saying the cabin crew earned an average of £16,000, including allowances, a year, but BA insisting no-one was paid below £21,000.
Unite national officer Oliver Richardson said: "From threats to the withdrawal of bonuses and travel allowances, the lengths that British Airways is going to to defend some of the lowest pay rates in the industry is shameful.
"We would urge British Airways to wake up to the determination of our members, who contribute massively to the billions of pounds in profits the airline generates, and get around the negotiating table to resolve the dispute."
BA said all its customers will fly to their destinations despite the industrial action, adding: "Our pay data shows that mixed fleet cabin crew who worked full time over the 12 months to last November earned more than £21,000 based on pay, allowances, incentive and bonus, and we have offered to let Unite carry out an independent audit of this data.
"Our pay offer for mixed fleet cabin crew is consistent with deals agreed with more than 90% of British Airways colleagues, including many Unite members."
The strikers will mount picket lines at Heathrow airport.