OpenSky Network is described as 'The OpenSky Network is a non-profit ADS-B exchange for sharing real time aircraft data broadcast over the airwaves. The network consists of thousands of sensors connected to the Internet by volunteers which collect ADS-B and Mode S broadcast data'. There are eight alternatives to OpenSky Network for a variety of platforms, including Online / Web-based, Windows, Android, iPhone and Android Tablet. The best alternative is FlightRadar24, which is free. Other great apps like OpenSky Network are RadarBox (Free), ADSBExchange (Free), FlightAware (Free) and Plane Finder (Freemium, Open Source).
The world’s largest co-op of ADS-B/Mode S/MLAT feeders, and the world’s largest public source of unfiltered flight data. Access to worldwide flight tracking data for hobbyists, researchers, and journalists alike.
PlanePlotter receives and decodes live digital position reports from aircraft and plots them on a chart. You can see a radar-like display of all those aircraft around you broadcasting digital messages including ACARS, ADS-B and HFDL.