London’s Heathrow airport, the busiest aviation hub of Europe, yesterday suspended all departing flights for a brief period following reports of a drone sighting. In a similar incident three weeks back, about 1,000 flights were grounded at the Gatwick airport.

Around 81 airlines serving 204 destinations operate out of Heathrow airport, located west of London. Arriving planes, however, continued to land at the airport.

The latest incident came few days after both the airports reportedly invested significant amount of money in military-grade anti-drone technology.