NOTAM : A new VATSIM client named swift is now there for all simulators, please use it instead of this. https://datastore.swift-project.org/page/about.php P.S. I don't use flightgear anymore, so I've absolutely no experience with this
Helps to connect Flightgear to VATSIM.
Tutorial http://thejabberwocky.net/viewtopic.php?f=23&t=1032#p20277
All credits to the respective authors.