British Airways blamed an unspecified technical issue for the delays and disruptions it has suffered on Thursday.
Flights to and from the UK’s Heathrow and Gatwick airports appear to be among those affected on Thursday.
"We plan to operate a full flight schedule today. There may be some knock-on delays to flights and we are advising customers to check ba.com for the latest flight information," the airline said in a statement.
"We are sorry for the disruption to customers who have been affected."
It's the latest in a series of systems failures to hit the airline in recent months. In August, an IT glitch led to the cancellation of more than 100 flights and left tens of thousands of passengers stranded.
Passengers have been advised to check the airline's website for updates.


Trump says Iran war deal close as Strait of Hormuz tensions linger
Fire breaks out at New Zealand's Wellington airport, disrupting flights
Ukraine and Russia trade overnight drone strikes, officials say
UN says Taliban arrest 30 women for violating hijab rules in Afghanistan
Trump cancels US strikes on Iran, citing progress in talks
South Korea court sentences ex-President Yoon to 30-year jail term in drone case
Thai king's eldest daughter dies, aged 47, after long illness
US confirms third strike on Indian-crewed tankers this week
