ADS-B Exchange has free and paid API services to those who set up a feeder to collect data and commercial users, respectively. The revenue from paid API access is used to offset the costs of collecting and storing the data. ADSBexchange data collection requires that one can freely participate...
ADSB.lol- A completely open-source and community-driven flight tracker that displays and providesODbL-licenseddata via afree APIas well asfree historical data. Community driven ADSBHub.org- A service for real-time ADS-B data sharing and exchange between plane tracking enthusiasts, plane spotters...