There were hundreds of delays on Saturday after the software used by several airlines failed, with affected airports boarding passengers using pen and paper. Brussels Airport said it had "no indication yet" when the system would be functional again and had asked airlines to cancel half their departing flights for Monday. RTX, which owns software provider Collins Aerospace, said it was "aware of a cyber-related disruption" to its system in "select airports" and that it hoped to resolve the issue as quickly as possible.

It identified its Muse software - which allows different airlines to use the same check-in desks and boarding gates at an airport, rather than requiring their own - as the system that had been affected. The company has yet to disclose what went wrong or how long it expects the outage to last, but said on Sunday it will "provide details as soon as they are available". Brussels Airport said only manual check-in and boarding are possible "due to a cyberattack against Collins Aerospace". It added disruption would continue into Monday "because Collins Aerospace is not yet able to deliver a new secure version of the check-in system". Heathrow said on Sunday that efforts to resolve the issue were ongoing. It declined to say whether or not the issue was a It identified its Muse software - which allows different airlines to use the same check-in desks and boarding gates at an airport, rather than requiring their own - as the system that had been affected. The company has yet to disclose what went wrong or how long it expects the outage to last, but said on Sunday it will "provide details as soon as they are available".

Brussels Airport said only manual check-in and boarding are possible "due to a cyberattack against Collins Aerospace". It added disruption would continue into Monday "because Collins Aerospace is not yet able to deliver a new secure version of the check-in system". Heathrow said on Sunday that efforts to resolve the issue were ongoing. It declined to say whether or not the issue was a cyber attack. It apologised to those who had faced delays but stressed "the vast majority of flights have continued to operate", urging passengers to check their flight status before travelling to the airport and arrive in good time. The BBC understands around half airlines flying from Heathrow were back online in some form by Sunday - including British Airways which has been using a back-up system since Saturday.

What are my rights if my flight is. It apologised to those who had faced delays but stressed "the vast majority of flights have continued to operate", urging passengers to check their flight status before travelling to the airport and arrive in good time. The BBC understands around half airlines flying from Heathrow were back online in some form by Sunday - including British Airways which has been using a back-up system since Saturday.  (BBC)