I like playing with tech stuff just to slow down the mind rot as I get older. We have a moderately active county airport here and I live almost directly under one of the IFR routes for east bound aircraft on their way to Atlanta. About three years ago lookin for something else to do with a Raspberry Pi (small, cheap single board computer) I found out it was pretty simple for them to process the ADS-B telemetry from aircraft.
The radio part is a cheap digital TV 'dongle'. All the hardware, except for the crappy cellular antenna, looks like this.
The Pi is loaded with the software from FlightAware, a flight tracking service/website I imagine most of you may already know about. This is connected by wi-fi to my home wireless router and then streams the aircraft data it hears to the FlightAware server.
If I connect to it locally on my network I get something like this on my laptop.
All the aircraft shown here on the map are the ones my shitty little setup is hearing directly.
Anyway, if you put something like this together Flight Aware gives you a free Enterprise account in exchange for you uploading data to them.
This local data is unfiltered. Some flights are redacted on their service after uploading.