Flightradar24 tracks positions of aircraft in real-time and turns that data into engaging consumer and business applications. The data comes primarily from a proprietary, crowd-sourced network of 40,000+ so-called ADS-B receivers hosted by private individuals and companies all over the world and tracks 200,000+ flights per day. This network of ADS-B receivers is the largest in the world.
In addition to ADS-B data, Flightradar24 is able to get positional data for non-ADS-B equipped aircraft through the use of Multilateration (MLAT). The ADS-B and MLAT data is merged with schedule and flight status data from airlines and airports to create a unique flight tracking experience. You can read more about how Flightradar24 works here:
http://www.flightradar24.com/how-it-works
Each day Flightradar24 has over 4 million unique users and our app has been the #1 selling app overall in Apple’s App Store in over 130 countries. Most airlines and many other companies in the aviation industry (including Airbus, Boeing and Embraer) use our services. The Flightradar24 app has been downloaded more than 75 million times. Flightradar24 is frequently featured in the media:
Wall Street Journal
http://www.wsj.com/articles/the-men-who-know-where-every-flight-is-1440610114
Reuters
http://www.reuters.com/article/2015/05/18/us-airlines-flightradar-idUSKBN0O31Q720150518
The Daily Mail
http://www.dailymail.co.uk/news/article-2204838/Rush-hour-skies-Real-time-map-shows-plane-air-right-now.html
Bild
http://www.bild.de/digital/handy-und-telefon/apps/neue-live-apps-fuer-das-smartphone-25031054.bild.html
Le Monde
http://bigbrowser.blog.lemonde.fr/2012/07/02/une-application-pour-savoir-ou-vont-ces-avions-qui-passent-dans-le-ciel