British Airways has said it will merge a "very small number of Heathrow services" during the upcoming 16-day walkout by cabin crew starting on Saturday.
All affected passengers are being contacted by the airline in advance, and the carrier said they will be rebooked onto alternative flights if they wish.
BA said in a statement:
Once again we will be able to fly all customers to their destinations, despite industrial action by mixed fleet Unite.
We will operate a full schedule at Gatwick and London City airports as well as the vast majority of our Heathrow schedule.
We will merge a very small number of Heathrow services, and all affected customers are being contacted in advance and will be rebooked to alternative flights.
Which airports are affected?
All flights to and from London Gatwick, London City and Stansted will operate as normal, along with the airline's weekend-only Mediterranean services to and from Birmingham, Bristol and Manchester. BA added that the majority of flights to and from Heathrow will operate as normal – but some are being merged.
What's the strike about?
Mixed fleet crew, who work on both long-haul and short-haul routes, are striking over a long-running pay dispute, with Unite union saying staff that had previously been involved in industrial action had been sanctioned unfairly.
How much disruption will there be?
The airline has been trying to minimise travel turbulence by applying to wet lease nine Qatar Airways aircraft and crew, though the union has called for the Civil Aviation Authority to refuse BA's application.
Unite national officer Oliver Richardson said: “It is an entirely avoidable waste of resources on behalf of British Airways and would not have happened, if the bosses had accepted our compromise offer on the outstanding issue of sanctions.
“Instead, British Airways faces the disruption of a two-week strike and legal action on behalf of over 1,400 mixed fleet cabin crew over the way it targeted striking members of cabin crew."