OpenSky Network is a non-profit research network collecting and sharing historical and live air-traffic surveillance data. It is primarily designed for researchers,...
Pros
- Strongest research and historical-data orientation among these options
- Provides APIs and datasets for analysis and experimentation
- Non-profit model is well suited to academic and open-data work
Cons
- Less convenient for casual live flight tracking than ADSB Hub
- API limits and access policies can constrain larger applications
- Does not offer the polished consumer alerts and airport tools of commercial services
Free for research and personal use; commercial access varies