Airports test unmanned traffic control towers
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.
At Ornskoldsvik, the planes are controlled by a person sitting 90 miles (144km) away at Sunsvall airport. That airport is due to have the same system installed later this year.
A spokesman for Saab told the BBC that the technology could be a huge benefit to air traffic control, reducing costs as small airports could pool controllers.
The technology can do a better job than humans, he said.
"The cameras and sensors pick up and see aircraft in any environment - in fog, rain and the dark. It is better than the human eye."
The system would also allow for pop-up airports that the military could deploy in war zones - attaching the system of cameras to trucks rather than towers.
He said that interest in the system is increasing, with some major airports considering installing remote towers as back-ups and added that the company is in talks with UK airports.
The UK's Nats said that it was in discussions with a number of manufacturers about offering the service in the UK.
"The introduction of remote control towers is one of the most exciting technological developments in the history of our industry," said Nats general manager of operations Paul Jones.
"We're excited by what remote towers could mean for airports' business,"