Locate your Flight in Real time:flightradar24.com

Flightradar24 shows live air traffic from around the world. The primary technology they use to receive flight information is called automatic dependent surveillance-broadcast (ADS-B). 
Flightradar24 has a network of about 500 ADS-B receivers across the world that receives plane and flight information from aircraft  and sends this information to a flightradar24 server, and then displays this information on a map on Flightradar24. Only aircraft with an ADS-B transponder, within the coverage area of the 500 receivers are visible.
Flightradar24 only have coverage in areas where someone has installed an ADS-B receiver and feeds his/her data into Flightradar24. If there are no connected ABS-B receivers in an area, then there is no coverage in that area.

In addition to ADS-B data, we also display data from the Federal Aviation Administration (FAA). This data provides full coverage of the airspace above the United States and Canada.
Flightradar24 covers about 90% of Europe. There is also some coverage in USA, Canada, Australia, Brazil, Middle East, Japan ,India and rest of world

Flightradar24 relies on volunteers around the world for the majority of our coverage. Find out how you can contribute.
Basic data flow in Flightradar24

Aircraft gets its location from a GPS navigation source (satellite)=>ADS-B unit on aircraft transmits signal containing about the location (and much and more)=>ADS-B signal is picked up by a receiver connected to Flightradar24 =>Receiver feeds data to Flightradar24

Today, roughly 60% of all passenger aircraft (70% in Europe, 30% in the US) are equipped with an ADS-B transponder. This percentage is steadily increasing as ADS-B is set to replace radar as the primary surveillance method for controlling aircraft.

In addition to ADS-B data, They also get data from the Federal Aviation Administration (FAA) in the United States. This data is based on radar data and includes all commercial air traffic in US and Canadian air space (i.e. not just planes with ADS-B transponders). Unlike the ADS-B data that is presented real-time, the FAA data is delayed by roughly 5 minutes due to FAA regulations. On the Flightradar24 map, all planes based on FAA data are orange.
Aircraft on Flightradar24

Common aircraft models that have an ADS-B transponder and are visible on Flightradar24:

    All Airbus models (A300, A310, A318, A319, A320, A321, A330, A340, A380)
    ATR 72-600 (most new deliveries)
    BAe ATP
    BAe Avro RJ70, RJ85, RJ100
    Boeing 737, 747, 757, 767, 777, 787
    Embraer E190 (most new deliveries)
    Fokker 70 and 100
    Gulfstream V, G500/G550
    McDonnell Douglas MD-10, MD-11
    Sukhoi SuperJet 100
    Some newer Ilyushin and Tupolev (for example Il-96 and TU-204)

Common aircraft models that do not have an ADS-B transponder and are NOT visible on Flightradar24:

    Antonov AN-225
    ATR 42, 72 (except most new deliveries of ATR 72-600)
    Boeing 707, 717, 727, 737-200, 747-100, 747-200, 747SP
    All CASA models
    All Bombardier Dash models
    All Bombardier CRJ models
    Dornier 328
    All Embraer models (except most new deliveries of Embraer E190)
    Jetstream 32
    Fokker 50
    McDonnell Douglas DC-9, MD-8x, MD-90
    Saab 340 and 2000
    "Air Force One"
    Most older aircraft
    Most military aircraft

There are lots of exceptions. For example one Lufthansa CRJ900, one LOT ATR-72, one Wideroe Dash, some MD8X from Onur Air, some Saab 340 in Australia and several private Cessnas are visible. There are also some older A300, A310, A320, B737, B747, B757, B767 aircraft flying without and ADS-B transponder, which make those aircraft invisible on Flightradar24.