The Eurocontrol agency has said that at least half of the flights across the continent had been affected. It stressed, however, that the problem did not pose any safety risks to passengers.
Nearly half of flights across Europe were facing delays on Tuesday after a flight plan glitch hit at the end of busy the Easter holiday period.
"Today 29,500 flights were expected in the European network. Approximately half of those could have some delay as a result of the system outage," the Eurocontrol agency said in a statement.
They added that the root of the problem "has been identified and action is underway to return to normal operations" by the late evening.
The agency stressed that the glitch had not posed any safety risks.
The delays, which one Eurocontrol official described to French news agency AFP as unprecedented, reduced flight capacity across Europe by 10 percent. Major airports like Amsterdam's Schipol warned passengers to check on the status of their flights.
Founded in 1960, the European Organization for the Safety of Air Navigation, commonly known as Eurocontrol, has 41 member states and has its headquarters in Brussels. The EU has delegated parts of its Single European Sky regulations to Eurocontrol. This makes it the central organization for the coordination and planning of air traffic control for all of Europe.
Travelers in France were hit particularly hard by the incident, as trains were already stopped due to a rail workers' strike called in protest of President Emmanuel Macron's labor policy reforms.
es/jm (AFP, dpa)