The My ADS-B page reports a local IP which is the IP of the interface used to route outbound traffic towards the FlightAware servers.
(specifically, it looks at the source IP named in
ip -o route get to 126.96.36.199)
I assume you are using a piaware sdcard image given that you’re managing the network config out of piaware-config. The piaware sdcard image, if configured for both wifi and wired ethernet, sets up default routes in parallel with the metrics set so that the wired-ethernet interface is preferred over wifi when both are up.
If you are not using the piaware sdcard image, then the network settings in
piaware.conf have no effect. They are sdcard image only settings.
If you have an unusual network configuration (routing traffic differently based on application counts as unusual) then the piaware sdcard image is not suitable for that - please start from a vanilla Raspbian image and configure the networking by hand as needed.