Air traffic control
Air traffic control is the service that directs aircraft on the ground and in the air, maintaining safe separation and managing orderly traffic flow.
Air traffic controller: A trained professional who directs aircraft and provides pilots with clearances, instructions, and safety information. Controllers issue the instructions that turn traffic plans into coordinated aircraft movements.
Controlled airspace: Airspace in which air traffic control service is provided according to defined classifications and procedures. Its classifications determine where and what kinds of control services apply.
Airport ground movement: The movement of aircraft and vehicles on airport taxiways, aprons, and runways. Ground control coordinates these movements to prevent conflicts and keep runways usable.
Flight information service: An aviation service that provides useful information and advice without necessarily directing aircraft or ensuring separation. It informs pilots but does not provide the control responsibilities of air traffic control.
Aviation safety: The management of risks to people, aircraft, and infrastructure across civil and military aviation. Air traffic control reduces collision and operational risks within the wider safety system.
Air traffic control clearance: An authorization specifying conditions under which an aircraft may operate, such as its route, altitude, or departure time. Clearances define the permitted route and movements controllers coordinate.
Flight plan: A document or electronic filing describing an aircraft’s intended route, timing, and other flight details. Filed plans give controllers an expected path against which to coordinate traffic.
Approach control: The air traffic control service that sequences arriving and departing aircraft near an airport. Approach controllers organize transitions between en-route flight and airport operations.
Traffic advisory: Information about nearby aircraft supplied to help pilots maintain awareness and avoid conflicts. Advisories support pilot judgment but are not equivalent to controller-provided separation.
Airspace sovereignty: A state's authority over the airspace above its territory, subject to international agreements and law. Control services operate within airspace responsibilities assigned by states and agreements.