Air traffic control aims to move aircraft safely and efficiently through the airspace system. Controllers keep aircraft set distances apart while moving them from airport to airport using set routes.

• In the UK aircraft in the airways system are handled by NATS.
• Air traffic control at airports is provided by a mixture of companies.

Before take off

Airlines will file a flight plan with air traffic control so every controller who deals with the flight on its journey is aware of its details and route.

When an aircraft is at an airport, the pilots on board will be in contact with controllers in the airports control tower. Air traffic controllers will look after the aircraft while it is on the ground and give it permission to take off.

In the air

Once airborne the pilot will then normally talk to another controller using a radar screen to track the aircraft’s progress through the airways system (equivalent to motorways in the sky).

Each controller is responsible for aircraft in a set piece of airspace. When an aircraft is nearing the edge of their sector they will coordinate its handover to the next controller. This will continue through the aircraft’s journey until it is handed over to the controller at the destination airport.

Most airliners are monitored by controllers using radar in airways and routes known as ‘controlled airspace’. The majority of airspace that is left is known as ‘uncontrolled’ and this is used by the military and recreational pilots. In this airspace some air traffic control services are provided, especially near airfields, but in much of the airspace it is the pilots’ responsibility to see and avoid each other.