Police gave the all-clear at Germany's Nuremberg airport after a suspected in-flight emergency involving a plane arriving from the Greek island of Corfu.
The alert prompted police to cordon off the airport and Eurofighter jets to escort the aircraft, which landed safely, an airport spokesman said.
Authorities confirmed later on Tuesday that the airport had resumed normal operations.
Coredon Airlines, which was operating the flight in question, said they believed an emergency signal had been sent due to a technical malfunction.
Why was the airport closed?
The DPA news agency reported that the plane had transmitted an emergency code before landing, alerting air traffic control to a possible problem on board.
"Checks at the scene established that there is no danger," police said in a statement. The nature of the alert was not immediately clear.
Earlier in the morning, three pilots independently reported seeing an object that may have been a drone while taking off or landing at the airport.
Airport officials, border police and Germany's air traffic control service immediately launched a search involving a police helicopter, but no drone was found.
Six flights were delayed, while two arriving aircraft diverted to Cologne and Prague before continuing to Nuremberg. It was initially unclear whether the two incidents were connected.
Drone incidents disrupt German airports
German airports have faced drone-related security alerts previously. In August, an explosives-laden drone was found near a runway at Leipzig/Halle airport, prompting a police investigation.
Leipzig drone threat prompts security concerns in Germany
In May, a possible drone sighting halted flights at Munich airport for about an hour, forcing more than 20 arriving aircraft to divert. Police found no drone.
Edited by Jenipher Camino Gonzalez and Wesley Dockery
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