A Fraport spokesman said that only a few flights were affected so far but did not provide an exact number. It was unclear how long it would take to fix the problem, he said, adding that Fraport's IT specialists had ruled out a cyber attack.
Frankfurt airport is Europe's fourth-largest, handling more than 60 million passengers in 2016. It has an average of almost 1,300 take-offs and landings per day.
(Reporting by Maria Sheahan and Tom Sims; Editing by David Goodman)
