The British Airways website was down for much of this morning and functioning slowly when it appeared.
The problems could cause major issues for passengers, who may be unable to check online whether or not their flights are due to leave.
The news comes as BA, like other airlines, grounds many of its flights from the Heathrow and delays departures from other UK airports. Heavy snow has hit many locations across the country.
BA had not explained the exact technology problems being experienced at the time of writing.
But the issue stems from heavy web traffic as the airline’s passengers go online to attempt check the status of their flights, and to reschedule flights when their existing bookings are cancelled.
An automated message on the BA.com homepage today, when it was not functioning, said only: “We regret to advise that this section of the site is temporarily unavailable.” The page did not offer any contact numbers.
Ba.com reappeared intermittently at various points this morning, with a message saying: “Due to high call volumes and website visits you may experience delays contacting us or changing your booking.” Pages at times take several minutes to load.
BA advised passengers not to go to the airports unless their flights were confirmed.