You're right that there isn't much air in space, but bowshock isn't specific to "air". There most definitely is bowshock in space: http://en.wikipedia.org/wiki/Bow_shock
The person mentioned supersonic, so I figured that's what the bow wave was referring to. Doesn't help that I work in aircraft and haven't been keeping up on my space knowledge lately ;) (And I don't work on cool military supersonic things, so my supersonic is rusty too...)
I still maintain you can't do do supersonic things in space. The would imply sound moves in space.
I still maintain you can't do do supersonic things in space. The would imply sound moves in space.