LONDON (AP) - Officials say a technical glitch that delayed or canceled hundreds of flights at Britain's busiest airports has been fixed.
National Air Traffic Services, which controls England's crowded airspace, said it had a problem switching between nighttime and busier daytime operations at its control center in Swanwick, southern England.
A spokeswoman said the problem with an internal communications system prevented staff opening new control positions to deal with busier daytime traffic, meaning the service was able to handle about 20 percent fewer flights than on a normal Saturday.
Heathrow Airport - Europe's busiest - had delays of an hour or more on many departures, and canceled more than 200 arriving and departing short-haul flights.
Officials said services began returning to normal about 12 hours after the problem was first reported.