Two drones that went floating over a runway at Gatwick Airport outside London this week caused chaos, disrupting hundreds of flights there, and stranding tens of thousands of passengers at England’s second-largest airport and elsewhere at the peak of the holiday season.

The drone disruption raises a host of questions, but for travelers in the United States, perhaps the most pressing is this: Could it happen here?

Here’s what we know.

What exactly happened at Gatwick?

Airport staff members first spotted the drones flying over a perimeter fence and into the runway area around 9 p.m. on Wednesday. Officials shut the runway, and then reopened it around 3 a.m. Thursday before closing it again about 45 minutes later when there was another sighting. Yet another drone was spotted late Thursday morning, and people kept spotting drones into Thursday night.

Officials called the move a “deliberate act,” but the police said there were “no indications to suggest this is terror related.”