Mysterious drone flights in NATO airspace have caused alarm across Europe. Heres what we know

BERLIN (AP) — Mysterious drone flights over the airspace of European Union member countries in recent weeks have alarmed the public and elected officials.

Intrusions into NATO’s airspace, some of them blamed on Russia, reached an unprecedented scale last month. Some European officials described the incidents as Moscow testing NATO’s response, which raised questions about how prepared the alliance is against Russia.

On Sept. 10, a swarm of Russian drones flew into Poland’s airspace, forcing NATO aircraft to scramble to intercept them and…