Airports are increasingly using unmanned air traffic control towers - relying on technology rather than humans to do a highly specialised job.
A remote system has just been rolled out in Leesburg Executive Airport in Virginia.
Sweden's Ornskoldsvik airport has had the same system - which uses cameras and sensors - since April this year.
The technology could revolutionise air traffic services, according to the UK's National Air Traffic Service (Nats).
The remote system - designed by Swedish defence firm Saab - includes 14 high-definition cameras and sensors that can spot aeroplanes in all weathers.
