Air traffic controller responsibilities are to inform pilots about nearby planes or potentially hazardous conditions, such as weather, speed and direction of wind, or visibility problems; monitor aircraft within a specific airspace, using radar, computer equipment, or visual references; maintain radio or telephone contact with adjacent control towers, terminal control units, or other area control centers to coordinate aircraft movement;

Alert airport emergency services in cases of emergency or when aircraft are experiencing difficulties; monitor or direct the movement of aircraft within an assigned air space or on the ground at airports to minimize delays and maximize safety; provide flight path changes or directions to emergency landing fields for pilots traveling in bad weather or in emergency situations; check conditions and traffic at different altitudes in response to pilots' requests for altitude changes; contact pilots by radio to provide meteorological, navigational, or other information; direct pilots to runways when space is available or direct them to maintain a traffic pattern until there is space for them to land; determine the timing or procedures for flight vector changes; transfer control of departing flights to traffic control centers and accept control of arriving flights;

Initiate or coordinate searches for missing aircraft; issue landing and take-off authorizations or instructions; compile information about flights from flight plans, pilot reports, radar, or observations; inspect, adjust, or control radio equipment or airport lights; direct ground traffic, including taxiing aircraft, maintenance or baggage vehicles, or airport workers; relay air traffic information, such as courses, altitudes, or expected arrival times, to control centers; organize flight plans or traffic management plans to prepare for planes about to enter assigned airspace; review records or reports for clarity and completeness and maintain records or reports as required under federal law; complete daily activity reports and keep records of messages from aircraft.

Analyze factors such as weather reports, fuel requirements, or maps to determine air routes; conduct pre-flight briefings on weather conditions, suggested routes, altitudes, indications of turbulence, or other flight safety information.