Half-term holiday plans for thousands of families were thrown into disarray after British Airways cancelled at least 42 more flights on Friday due to the impact of an IT failure.
Most of the affected flights were on short-haul routes to and from Heathrow Airport on what was expected to be the busiest day for UK air travel since before the coronavirus pandemic.
Friday’s chaos was caused by planes and crew being out of position after an IT problem caused around 80 flights to be grounded on Thursday.
Around 16,000 passengers have been affected by the cancellations.
There were also widespread delays to other flights, and some passengers were unable to check in online.
A British Airways spokeswoman said: “While the vast majority of our flights continue to operate today, we have cancelled some of our short-haul flights from Heathrow due to the knock-on effect of a technical issue that we experienced yesterday.
“We’ve apologised to customers whose flights have been affected and offered them the option to rebook to an alternative flight with us or another carrier, or request a refund.”
The airline added that where possible cancellations have been focused on routes with several daily flights, enabling passengers to rebook at alternative times.
Heathrow said the problem was not related to a strike by security officers at Terminal 5.
British Airways has suffered a series of IT failures in recent years.
Aviation analytics firm Cirium said Friday was expected to see the most departures from UK airports since December 20 2019, with more than 3,000 flights planned.
This is due to many families heading overseas ahead of the half-term school holiday in England and Wales.
A tweet from British Airways at 11.27pm on Thursday said its “systems are back up and running” but there might still be “intermittent issues”.
Customers can receive refunds, rebook or if they have to stay overnight they will be offered meals and hotel accommodation.
One Twitter user, who was at Heathrow at around 7pm on Thursday, said: “Almost all BA flights from LHR T5 (London Heathrow Terminal 5) cancelled tonight. No info. About 4 people on BA desks trying to deal with the chaos.
“Come on BA you can do better than this. You are supposed to be the UK’s flagship.”
Ferry operator DFDS said shortly before 8.30am that there was a wait of around an hour at border control for travellers in cars, while coach traffic was “free-flowing”.
This comes after coach passengers at the Kent port suffered delays of several hours ahead of the Easter school holidays.
The RAC estimated that drivers across the UK will embark on 19.2 million leisure car trips between Friday and Monday as people make the most of the bank holiday weekend.
Transport data company Inrix warned that journeys on some stretches of the M25 will take up to three times longer than normal.
They include clockwise from Junction 23 for Hatfield to Junction 28 for Chelmsford, and anticlockwise towards the Dartford Crossing.
Long delays are also expected on the M5 in Somerset and the M6 in Cheshire and Greater Manchester.