Holidaymakers may be swept up in aviation chaos when British Airways cancels around 32 flights a day at Heathrow over Easter.
Over the Easter weekend the British flag carrier will significantly reduce its inbound and outbound Heathrow flights due to a strike by security guards at the airport.
Members of the Unite union will walk out for 10 days from Friday in a dispute over pay after talks to avert the action failed last week.
Heathrow said it was putting "contingency plans" in place and drafting 1,000 extra staff - as well as its management team - into terminals to help passengers during the Easter getaway.
A BA spokesperson said: "Following Heathrow's requirement for us to reduce the number of passengers travelling during the period of its employees' proposed strike action, we've regrettably had to make a small number of adjustments to our schedule.
Are you impacted by the cancellations? Email webtravel@reachplc.com
"We've apologised to customers whose travel plans have been affected and have offered them a range of options, including rebooking on to a new flight with us or another airline, or requesting a full refund.
"Our teams are continuing to work closely with Heathrow to ensure that our customers' journeys run smoothly."
British Airways has cancelled around 5% of its flights during the industrial action and stopped selling tickets for strike days.
The cancellations fall on short-haul routes meaning long-haul services are not affected.
BA has not released a list of the flights which are cancelled, but those affected will be contacted, the airline has said.
Routes which are serviced by multiple flights a day are more likely to face cancellations as BA tries to group passengers together on single planes.
BA customers have been offered free hand-luggage checking to try and reduce time in security queues.
All of the airlines services from London City Airport and Gatwick are currently unaffected.
A Heathrow spokesperson said: "We will not let these unnecessary strikes impact the hard-earned holidays of our passengers.
"Our contingency plans will keep the airport operating as normal throughout.
"We are deploying 1,000 additional colleagues and the entire management team, who will be in the terminals providing assistance to passengers over the busy Easter getaway.
"As at any busy time, it may take a little longer than usual to get through security, but this will be well-managed and kept flowing.
"Passengers can help us ensure they get the best start to their journeys by checking their flight status with their airline before travelling to the airport, arriving at Heathrow no earlier than two hours before short-haul flights and three hours before long-haul flights, and by being ready for security with their compliant liquids and electronics out of their hand luggage."
