How do I implement ADS-B aircraft tracking using a low cost RTL-SDR dongle?

Implementing ADS-B (Automatic Dependent Surveillance-Broadcast) aircraft tracking using a low-cost RTL-SDR dongle receives and decodes the 1090 MHz transponder signals broadcast by aircraft, providing real-time aircraft position, altitude, speed, and identification data. The setup requires: an RTL-SDR dongle (any RTL-SDR works at 1090 MHz; the RTL-SDR Blog V4 ($30) includes a built-in 1090 MHz bandpass filter and LNA, optimized for ADS-B), an antenna (a 1090 MHz quarter-wave ground plane antenna: a vertical element approximately 69 mm long (lambda/4 at 1090 MHz) with 3-4 radials, mounted outside with clear sky view; gain: approximately 3-5 dBi; for better range: a collinear antenna (multiple stacked elements) provides 6-9 dBi gain and a narrower beam in the elevation plane, improving the reception range to 200-400+ km), decoding software (dump1090: the original open-source ADS-B decoder for RTL-SDR (written by Salvatore Sanfilippo); receives the 1090 MHz signal, decodes Mode S and ADS-B messages, and displays aircraft on a local web map. readsb: a modern, actively maintained fork of dump1090. tar1090: a web-based frontend for visualizing the decoded aircraft data), and optional: feeding services (FlightAware PiAware, FlightRadar24, ADS-B Exchange: these services accept your decoded data and provide free premium accounts in exchange for your feed; the most popular use case for ADS-B SDR setups).