UK National Air Traffic Services (Nats) said on Friday evening a technical fault in the flight data system at its Swanwick centre had caused flight disruption.
The government said the disruption was "unacceptable" and demanded a "full explanation" of what had gone wrong.
The glitch caused problems at airports around the country - including delays at Heathrow and Gatwick, where departing flights were grounded for a time. Other UK airports reported knock-on effects. According to BBC, 84 flights were cancelled at Heathrow on Friday, and that delays are under an hour.