The Economist wrote about the control tower outsourcing business:

• Instead of having an elevated air traffic control tower some airports are opting to install cameras that transmit video to a low-rise office building several hundreds of kilometers away.
• The system can boost safety. Cameras including infrared ones allow operators to see what typical control towers can’t. And remote centers can do things like zoom on video or project augmented reality displays with distance approach counters.
• The system cuts costs. Airports no longer need to build elevated tower structures. And a single remote center could control multiple airfields.
• Some regional airfields don’t have any kind of landing control. Instead pilots keep a sharp eye and state their landing plans to other planes in the area on an open radio line. Such airfields could now afford to have air traffic control.
• Nordic populations scattered across isolated settlements have been the primary benefactors of the system.
• But other, larger airports are being targeted. Operators initially make inroads by selling it as a contingency tower in case of emergency.
• There are fail safes if the remote towers ever go offline. In the future a network of them could act as each others’ fail safes.

Read more on The Economist.