Air traffic resumed in London Friday evening after a technical failure at an air traffic control center caused officials to restrict access to the country's airspace.
The National Air Traffic Service said the technical problem happened in Swanwick -- just outside Southampton.
At London's biggest airport, Heathrow, where flights have now resumed, no flights were taking off or landing for at least an hour.
Gatwick, south of the capital, said flights there were departing, but with delays.
A government official told Reuters that the problems did not appear to be linked with any security threat.
It's unknown how many travelers were affected by the failure, but officials said it would take time for operations to fully return to normal.
