HI I can tell you exactly how I installed it according to the instructions on the flightaware site. I installed piaware only as I already run fr24feed. These are the exact instructions I followed:
Download and install the PiAware repository package, which tells your Pi’s package manager (apt) how to find FlightAware’s software packages in addition to the packages provided by Raspbian.
For Raspberry Pis running on Raspbian Buster OS , execute the following commands from the command line:
sudo dpkg -i piaware-repository_3.8.1_all.deb
For Raspberry Pis running on Raspbian Stretch OS , click here
This will download and install PiAware and required dependencies on your Raspberry Pi.
sudo apt-get update
sudo apt-get install piaware
This will enable automatic and manual (web-based, via your request) PiAware software updates. These updates are disabled by default. To leave updates disabled, skip this step.
sudo piaware-config allow-auto-updates yes
sudo piaware-config allow-manual-updates yes