Almost 70 flights into and out of Germany's busiest airport were canceled as faults with traffic control software continue. Airspace in the region will run at 75 percent capacity until safe conditions are restored.
Sixty-six flights to and from Germany's busiest airport Frankfurt were canceled on Monday amid ongoing technical problems affecting air traffic control.
Around 4,500 passengers traveling with the German airline Lufthansa were affected when 46 of its flights were scrapped.
A "software malfunction" has caused problems at the state-owned air navigation service provider DFS since last Wednesday, the company said, but assured the public that "the safety of air traffic is not impaired."
Until new software is installed on Thursday, air traffic has been reduced to 75 percent capacity for safety reasons, impacting flights using Frankfurt, Cologne-Bonn, Stuttgart and Düsseldorf airports.