Believe it or not, the ideal way to weather a jumpsuit or flightsuit is to wear it and then roll around outside like a kid. Do power slides, slide into home base, fall down, etc. Do this in a very sandy area as it will wear out the fabric nicely. You'll look like a total dork, but it works. For my Boba's cape, I shot holes in it with a shotgun slug (of course I live way out in the backwoods). If you are really artsy, you can just use differing colors of tempera paint (greys, browns, etc.) and make it look weathered that way. Just some suggestions. I am going to be weathering my black jumpsuit on my custom in this way.
I haven’t even thought about weathering my flightsuit yet. What would you suggest for doing that?