ADS-B
Automatic Dependent Surveillance–Broadcast. Equipped aircraft can broadcast information that includes position, altitude, ground speed, and identification to compatible receivers.
Learn moreAviation reference
Flight tracker glossary
Understand the identifiers, surveillance terms, speeds, directions, and airport codes commonly shown on aircraft and flight-tracking services.
Squawk code
A Mode A transponder code used for air traffic surveillance. It is not the same as a flight number or a permanent aircraft identity.
Learn moreCallsign
An identifier used in operational radio communication. For airline operations it can relate to the operator and flight identification used by air traffic control.
Flight number
A commercial airline service identifier, usually combining an airline designator with a number. The operating flight can differ from a marketing codeshare number.
Learn moreTail number / registration
A civil aircraft registration identifier assigned under a national registration system. It identifies the aircraft, not a scheduled airline service.
Transponder
Aircraft equipment that responds to surveillance interrogations and can support transmission of identifying or altitude-related information.
Altitude
Vertical position expressed relative to a reference. Public trackers may display pressure altitude, geometric altitude, or a processed value depending on the source.
Heading
The direction the aircraft nose is pointing. Wind can make heading different from the actual path over the ground.
Track
The aircraft’s direction of movement over the ground. It can differ from heading because of wind.
Ground speed
The aircraft’s speed relative to the ground. It is different from airspeed, which measures motion relative to the surrounding air.
IATA code
A three-character location or airline designator commonly encountered in passenger booking, schedules, ticketing, baggage, and other commercial processes.
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A four-letter location indicator used for operational aviation purposes. Many major contiguous-U.S. airports use a K-prefixed form of their familiar IATA code, but that pattern is not universal.
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A unique 24-bit address assigned to an aircraft. It is distinct from the squawk code, registration, and flight identifier.
Radar
Ground-based surveillance technology that determines aircraft position using radio energy. Radar and ADS-B work differently and can complement one another.
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