Build a Aircraft scanner from a Pi 3 and an RTL-SDR radio dongle and external audio PC speaker.
Full details are available at https://github.com/szpajder/RTLSDR-Airband/wiki
- Raspberry Pi 3 with at least 2 USB slots
- RTL-SDR Dongle V3 (typical one, not ADS-B!)
- USB powered speaker with stereo audio plug
- Antenna with connecting cable for RTL-SDR dongle