Flights to and from Germany’s largest airport, Frankfurt, were suspended twice on Monday following drone sightings.
A spokesman for operator Fraport said 72 flights were cancelled and 57 redirected during the stoppages, which lasted three hours.
Police were looking for the perpetrators and their drones and criminal proceedings were launched for dangerous interference in air traffic.
“In addition, the perpetrators must expect considerable claims for damages under civil law,” police added.
In one of the worst drone air traffic disruptions, reported sightings near London’s Gatwick airport caused chaos for thousands of Christmas travellers in December 2018.