A technical problem that forced authorities to impose flight restrictions in the UK has now been fixed and traffic control systems are returning to normal.
An untold number of flights were affected by the fault, which appears to have been a power outage involving computer systems.
It is expected to take some time before a backlog of delayed flights starts to clear.
Authorities had earlier said airspace restrictions would stay in force until 8pm Central European Time while the problem was fixed.
At the height of the technical failure, London’s biggest airport, Heathrow, said no flights were taking off or landing.
Gatwick reported delays, while Stansted talked about flights being suspended.
Government sources were quoted as saying the problems did not appear to be linked to any security threat.
Other airports in the UK say they had offered to take any of the diverted flights.