Property Tree/Web Server
And, just for fun we have an embedded web server you can activate which exposes the internal property tree via a web style interface that you can browse (and edit) with any web browser. You can literally fly the airplane remotely via your web browser. It's primarily there as an interactive remote debugging tool, but it could be used for many things.
To view the PropertyTree with a web browser, start FlightGear with the following option:
where 5480 is the port number. You can pick any port number, but 5480 will probably work just fine.
On the same machine, fire up a web browser and open up the following url:
You can now browse the entire FG property tree "live" as the sim is running. You need to refresh the browser to see changes and you can even change values if you like. You can configure autopilot modes and even set control inputs so you could literally fly the airplane from your web browser, although it's maybe not the most convenient interface for doing that. ;-)