I recently became interested in aviation through hearing helicopters overhead and wondering where they were going. Through apps like FlightRadar24 and airplanes.live you can track aircraft across the globe, with airplanes.live providing a free, easy-to-use API for tracking aircraft. Especially useful for this specific project is an interface that lists data for aircraft within a radius of a given coordinate. It's also possible to track aircraft local to you by using an ADS-B receiver. ADS-B is a primary means of communication by aircraft to broadcast their location, and you can capture these signals by listening on 1090 MHz for the majority of aircraft.