British Airways canceled almost 100 flights to and from London airports on Wednesday after its check-in systems were hit by computer problems.
The airline said a "systems issue" was causing delays and cancellations for short-haul flights from Heathrow, Gatwick and London City airports.
British Airways said it was relying on back-up and manual systems, and canceled 81 flights due to operate to, or from Heathrow, and 10 Gatwick flights, stranding some 15,000 passengers. More than 200 other flights were delayed.
"A number of flights continue to operate but we are advising customers to check ba.com for the latest flight information before coming to the airport," the airline said in a statement.
BA said short-haul passengers due to travel Wednesday could re-book for another day.
In May 2017, tens of thousands of passengers were stranded when a global computer failure grounded hundreds of British Airways flights over three days. BA passengers were also hit with severe delays in July and September 2016 because of problems with the airline's online check-in systems.
The airline is also set to be fined 183 million pounds ($222 million) over a cyberattack on its security systems last year in which the personal data of up to 500,000 customers was stolen.