Germany’s Frankfurt Airport was suspended for 29 minutes after a drone was spotted in the area, Friday, March 22, according to the Associated Press (AP). Two drones were cited originally, but later that number was revised.

After the federal police’s helicopter surveyed the area, the site was clear of any drone activity.

In addition to drones, Friday brought more delays at Frankfurt Airport. Due to an unrelated computer problem at an air traffic control center, “60 of Friday’s 1,439 scheduled Frankfurt flights were canceled,” AP reports.

As it seems, the drone versus airport narrative continues. At the beginning of the new year, Newark Liberty International Airport had to ground all departing and incoming flights in response to a drone flying within 30 ft of an aircraft. A month later, Dubai International Airport and Ireland’s Dublin Airport suspended flights after suspected drone activity. 

London’s Gatwick also suffered a sizeable blow, shutting down for three days during the Christmas travel rush, which delayed more than 100,000 people.

To avoid this from happening again, the U.K.’s Department for Transport extended the drone “no-fly” zone from 1 km to 5 km around airport runways, effective March 13.