There are quite a few mobile apps and also web sites that allow real-time flight tracking presenting data with the aircraft overlaid on a map. There are a few places to access this flight data and one which we have found driven by a worldwide community of participants is ADS-B Exchange. This site is co-op of ADS-B/Mode S/MLAT feeders from around the world, and the world’s largest source of unfiltered flight data. And if you want to join the community and feed air traffic in your area then this can be achieved at low cost with a Raspberry Pi.
In the FPAssistant SDK we have developed some classes that will read the flight data offered and return collection of data, this can be all the live feed data or a subset returned by spatial query using a GeoCoordinate point and radius around. This feature will be added to the FPAssistant app later this year.