The first alarm came at around 8pm on Tuesday evening and concerned Zaventem Airport in Brussels.
For safety reasons, all air traffic has been temporarily closed, Kurt Verwilligen, spokesman for the air traffic control service Skeyes, explained to Le Soir.
Several flights were initially diverted to the airport in Liège – but it was also closed shortly afterwards after further alarms there as well.
At 9:30 p.m., traffic to Brussels was able to resume. But just over fifteen minutes later, new reports came in that traffic was down again.
The police have seen two drones over the airport, said Mayor Kurt Ryon of Steenokkerzeel to the newspaper Het Laatste Nieuws (HLN).
Among the planes that were rerouted, including via Ostend, were flights from Gothenburg, Munich and Oslo.
Only after 11 p.m. was HLN able to report that traffic to Brussels was back on track.
Belgian Defense Minister Theo Francken was on a television broadcast that evening, which he left in the middle of, due to the alarms.
"My place is not here right now," Francken said and left.
Recently, there have been several reports of drones being seen over Belgian airports.
