British Airways expects most flights from Heathrow to operate as usual although flight timings may change during a 48-hour cabin crew strike next week.
The airline stressed that all passengers will be able to fly to their destinations on January 10 and 11 despite the action by Unite members of the so-called mixed fleet at Heathrow.
“The vast majority of flights to and from London Heathrow will operate as normal,” BA said.
However, the carrier added: “As part of our contingency plan, we will be merging a very small number of flights to and from Heathrow.
“This will mean some customers will travel slightly earlier or later in the day than their original booking.
“Customers affected are being contacted with the options available for them.”
All flights from Gatwick and London City airport will operate as normal.
BA added: “We look forward to welcoming more than 200,000 customers onto our flights across the two days and ensuring they can all proceed with their holiday breaks, visits to friends and family or business meetings.
“Customers can book flights as normal through all of our usual sales channels including ba.com.
“We urge Unite to abandon its strike plans which are serving only to cause anxiety among our mixed fleet cabin crew colleagues who do a tremendous job for our customers.
“We continue to be available for further dialogue with Unite.”