Gaming Freeware air combat sims, any good ones?

[Linguofreak]

I think the thread title pretty well describes what I'm asking.

 

[Andy44]

I think Falcon 4.0 is now a freeware program, since Microprose went belly-up years ago. Last time I checked there were two different groups out there working on seperate F4.0-related projects.

 

[Jarvitä]

Ysflight, although it is rather simplistic and minimalistic, especially without any addons.