By Laura Sharman, CNN(CNN) — Munich Airport in Germany was forced to close for almost seven hours overnight after a wave of drone sightings, the latest European aviation hub to shutter over unexplained drone flights. Drones over western EuropeMunich becomes the latest European airport to close after sightings of drones nearby. At the summit leaders were expected to discuss several measures intended to protect the continent’s skies, including a flagship “drone wall” initiative. The drone wall initiative would not be a physical wall, but instead a layered network of detection and interception systems, building on individual EU members’ anti-drone capabilities. Not to France, not to Denmark, not to Copenhagen,” he joked, in reference to the drone flight allegations.