'This was a worldwide failure': How airports were affected
Frankfurtairport operator Fraport said that Germany's largest carrier, Lufthansa, and partner airlines had been hit by a problem for around 30 minutes that prevented bags being checked in, but said the issue had been resolved.
A spokesman for Groupe ADP, which operates more than a dozen airports in the greater Paris region, confirmed airlines using the Amadeus system had been affected at the French capital's Charles de Gaulle airport.
"This was a worldwide failure (of the Amadeus system). We were no worse affected than other airports. It only lasted a few minutes," the spokesman said. He said national carrier Air France was among the airlines that used Amadeus.
In Washington, a spokesman for the Metropolitan Washington Airports Authority said Southwest Airlines reported a computer issue causing a few minor delays at Reagan National Airport of up to 16 minutes but there were no other issues at present.
What might passengers be entitled to if flights are delayed?
Passengers whose flights are delayed as a result of the IT glitch should be entitled to compensation if it is not classed as an "extraordinary circumstance".
Paloma Salmeron Planells, from flight delay compensation company AirHelp, said:
“Following the news of Amadeus Altea check-in software crash, passengers worldwide could miss their holidays, lose their luggage or even be left stranded in the airport.
“Depending on the situation an IT glitch might not be regarded as an ‘extraordinary circumstance’, so if your flight is delayed or cancelled you could be entitled to up to £510 in compensation.
"In addition to this, the airline should provide you with meals, refreshments, access to phone calls and emails and if necessary, overnight accommodation.
“Amadeus Altea services 64 per cent of the Star Alliance, 75 per cent of One World and 53 per cent of the Sky Team, which means the issues with the software could affect over 120 airlines, including BA, AirFrance, KLM and Lufthansa."
KLM also reporting check-in problems in the Netherlands
KLM in the Netherlands is reporting problems, reports Senay Boztas.
In reply to a customer's request on Twitter, the airline said: "We are still experiencing technical issues at this moment.
"Unfortunately we cannot give you a time-frame at this moment."
Video shows length of queues at Gatwick Airport
While queues at Gatwick have now subsided after a spokesman said the systems were "back up and running", this video shows how long queues were at the Thomas Cook check-in desk earlier:
Heathrow 'working closely with airlines to solve issue'
A small number of airlines are experiencing problems across the world & we're working closely with them to solve the issue.
— Heathrow Airport (@HeathrowAirport) September 28, 2017
Software firm: 'Services are gradually being restored'
Amadeus, the company that provides check-in software for more than 100 airlines around the world, has confirmed it is experiencing a "network issue that is causing disruption".
“Technical teams are working on the problem, services are gradually being restored," it is reported to have said.
Heathrow confirms airlines at terminals 2, 3 and 4 affected
Heathrow Airport has confirmed that airlines at three of its terminals have been experiencing systems problems that have caused check-in delays.
A spokeswoman said:
"A small number of airlines are currently experiencing intermittent issues with their check-in systems at airports around the world - including at Heathrow.
"Passengers will still be able to check-in for their flight, although the process may take slightly longer than usual.
"We are working closely with our airlines to help resolve the issue as quickly as possible. We apologise for any inconvenience this may cause."
Several airlines at Terminals 2, 3 and 4 are affected.
'Pack patience': Passengers report huge check-in queues
When you've been looking forward to your holiday all year and then all computers at airport crash as you are checking in. ALL SERVERS DOWN 😣
— SFW (@cinnamonwalsh) September 28, 2017
So this airport has no air con and now our flight has been delayed, can today get any worse ?? @jet2tweets
— Jord❃ (@Jordaancox_) September 28, 2017
So this airport has no air con and now our flight has been delayed, can today get any worse ?? @jet2tweets
— Jord❃ (@Jordaancox_) September 28, 2017
Update: 'Things back up and running' at Gatwick
Gatwick Airport has just got back in touch.
"Things are back up and running after a momentary IT glitch," a spokesman said.
It is not clear if the issue has been fixed at all airports
Gatwick Airport: Check-in software affecting multiple airlines
A Gatwick Airport spokesman said: "This is an airline issue, not an airport issue. This isn't Gatwick software, it's hit a few airlines' check-in systems which are down.
"They are using Altea software and there are several airlines that use the same software for check-in and it's that which is affected.
"They cannot check the passengers in."
The spokesman could not confirm which airlines are affected.
All systems are down at OR Tambo International 🙈 back to the manual way 🙈🙈🙈
— Althea Campbell (@AltheaCampbel14) September 28, 2017