Long queues at the Thomas Cook check-in desks at Gatwick Airport on Thursday morning Credit: Jerry Gandhi/Twitter Passengers struggle to check-in due to systems failure'Glitch' with software used by 125 airlines from 10.30amDelays at airports including Heathrow and GatwickProblems also appear to affect some online check-insSoftware firm confirms 'network issue' caused disruptionSystems 'recovered'