British Airways has cancelled short-haul flights to and from Heathrow on Saturday due to ongoing technical issues.
The major outage has caused cancellations and delays of flights, pile-ups of luggage and passengers stuck on planes after landing at Heathrow.
The airline said the problem is related to a hardware issue and is not because of a cyber attack and that they "anticipate further disruption during the day".
Some arrivals and departures at Belfast City Airport have been affected.
The 8.05 BA1414 arrival from London Heathrow this morning was cancelled, with two London Heathrow departures also being called off.
BA’s website and app were inaccessible for hours on Friday evening, preventing customers from checking in online or booking flights.
On Saturday morning, the airline advised customers to check the website for the latest flight information before coming to the airport.
In a statement, BA said: “We are extremely sorry that due to the continuing technical issues we are facing we have regrettably had to cancel all short-haul flights from Heathrow today until midday.
“Customers due to travel later today should check their flight status on ba.com before coming to the airport as we anticipate further disruption during the day.
“Our long-haul services at Heathrow and all flights at Gatwick and London City Airport are due to operate as planned, but customers may experience some delays.
“Our website ba.com is working and customers can check-in online and at the airport.”
