Wow.... Does anyone use Unix any more? I know when I worked a couple of contract Aerospace jobs the only solid modeling Software was Catia.... and it ran on Unix... of course ProE and Solid Works have become the work horses in that area but I am sure there are specifics for the government.
Catia could handle the WHOLE database of components for an airplane. The 777 was designed soley in Catia... We used that database to create tooling for the plane. Unfortunately they didnt have tool desingers that could run Catia... So we were called in to draw them up by hand. Work platforms are considered tooling. We could do it faster on paper...
There are still some Unix systems out there. Mostly some type of Linux is used. Our new sites are Linux running a Drupal Stack. We are still getting used to Drupal, which is a web server platform.