Flights at London Gatwick were grounded for more than 19 hours, stranding tens of thousands of travelers, forcing flights to reroute and sending disruption rippling through European transit networks. The culprit? Easily available drones flying illegally over the runway, preventing planes from taking off and leaving London’s second-busiest airport in chaos.

The ongoing shutdown at Gatwick demonstrates how even small disruptions can have serious consequences for key infrastructure that current security is ill-prepared to address. After all, even the best body scanners and strictest bag searches aren’t going to stop an off-site drone operator.