a nice flight sim for Linux (i believe it works with Unix to right?) is called flight gear.... you can download it for FREE at
www.flightgear.org it's a big download.... but it's a great sim.... i'm new to linux so i don't know how to use it very well... but i got it to run ok

i found out about it at Linux world about 2 years back... and next linux world (this august) at Sanfrancisco CA i'm going to be a helper in the booth

check it out.....
David