How flight status actually works

Schedules come from airlines

Scheduled departure and arrival times, terminals, gates, delays and baggage belts all originate in airline and airport systems. They are authoritative, they are what the departure board in the terminal shows, and they are distributed commercially. FlightStatus does not have them.

Positions come from the aircraft

Almost every airliner broadcasts its identity, position, altitude and speed continuously, in the clear, on a system called ADS-B. Anyone with a small receiver can hear it, and volunteers worldwide feed what they hear into open networks. That is what FlightStatus runs on.

Which means

• Where an aircraft is, FlightStatus can tell you exactly — and how many seconds ago that was heard.
• Whether it is late against its schedule, it cannot, because it has no schedule to compare against.
• An arrival estimate is arithmetic on distance and speed, not an airline’s own forecast.
• Silence means no receiver can hear it — not that the flight is not operating.

Why coverage has gaps

ADS-B is line-of-sight and needs a receiver on the ground. Over land in Europe, North America and much of Asia, coverage is dense. Over oceans, the poles and sparsely populated regions, there may be nobody listening — so a transatlantic flight commonly vanishes for hours in the middle and reappears on the far side. That is normal.

Try it

Track a flight by number, or open an airport board.