FlightGear is a collaborative project that aims to create a sophisticated free, completely open-source flight simulator
Its not as bad as you make it sound. Free as in Free Beer, yes, and its not quite on par with Flight Sim, but I refuse to use Windows as a platform for anything, and as flght sims go FG is pretty damn good for free.
It’s a terrible-looking game, quite honestly. Still, this is Linux we’re talking about (and yes, I’m a fan of Linux). As long as the community is relying on FREE help this is the type of quality you will get.
Flight Gear is really sweet. You can fly all over the world an in a variety of aircraft by downloading files from their website. I first found out about this several months ago after I installed it in Mint and I’ve been in love with it ever since. The scenery isn’t quite as good as what you’d find in a commercial flight sim but it’s free and really great, lots of fun.