Here are a couple of flags I have designed in the past:
This one I use currently, and I only designed it a couple of days ago:
These are a couple of similar ones from a while ago:
And some from my abandoned DSK (Deep Space Kerbal) Career save:
All made on Paint.net
Wow! Some of these stations look amazing! I've been thinking about doing a spaceplane hangar in space idea like Good_Cat for a while, I will have to get something up here when the KSS Ersten and the KSS Artemis are complete!