A temporary disruption in the German air traffic control system led to problems throughout German airspace, air traffic control said on Friday.
The malfunction, which has now been resolved, led to delays and cancellations.
The disruption led to the loss of flight plans and weather data in particular, the agency said.
“The fault has been resolved and the systems have been running again since 10.25 am [0825 GMT].” However, the data lost during the disruption would have to be re-entered, the report said.
At Germany’s largest airport in Frankfurt, there were “significant delays in operations and flight cancellations,” according to airport operator Fraport’s website.
The company said there were about 100 cancellations by noon. Other airports such as Berlin, Düsseldorf and Stuttgart were also affected.
“We do not expect many more cancellations as the issues have been resolved,” a spokesperson said.
A Lufthansa spokesperson said there were isolated flight cancellations and delays and that long-haul flights were not affected.
There could still be some impact on the network on Friday and the airport operator advised passengers to regularly check flight status on the relevant airlines’ websites.