Britain's National Air Traffic Services (NATS) was hit by a technical problem for several hours on Monday, causing widespread disruption to flights using the United Kingdom's airspace. NATS had earlier had to restrict the flow of aircraft after the issue affected its system's ability to automatically process flight plans, with airlines and airports warning of delays and cancellations. "We have identified and remedied the technical issue affecting our flight planning system this morning. We are now working closely with airlines and airports to manage the flights affected as efficiently as possible," NATS said in a statement later on Monday. "The flight planning issue affected the system's ability to automatically process flight plans, meaning that flight plans had to be processed manually which cannot be done at the same volume, hence the requirement for traffic flow restrictions."