I recently (Aug 2017) set up a PiAware flight tracking receiver. The Pi in PiAware refers to a Raspberri Pi computer and the Aware is part of a larger concept by the FlightAware Company. In the case of PiAware volunteers purchase Raspberri Pi computers, a USB receiver module, antenna and coaxial cable. Since I already had a Raspberri Pi gathering dust I only had to purchase the receiver to start tracking. Here's a link if you would like more information.
The photos and screen captures to the right document the receiving station and the antennas I deployed. The charts signify the number of aircraft picked up with each configuration. The radial charts give a clear indication of how the station performed as higher quality antennas were added.
If you subscribe to the Amateur Radio Relay League publication QST, you might have read the article "Aircraft Tracking, Flight Aware, and How You You Can Be of Service" in the August 2017 issue. This caught my interest and led me to the PiAware web site.