Some ideas I think we may need to do:
We might want to combine the sections on setting and campaign into a single chapter because having them reference each other might make more sense.
Also, I'd like to see three ways of integrating the Cosmo into a game:
1) Flight is the primary theme/hook of the setting. Nearly all adventures involve flight. In this system, different character classes have default Proficiencies with vessel types much like character class do with armor and weapons. Extending your proficiency into other vessels requires feats. A number of new skills should also be included. Navigate, engineering, Specific Science sub-groups, etc. Maybe even Pilot and Engineer Core classes.
2) Flight exists in the setting but is not the primary concern of the setting, much like mounted combat in normal DnD. Feats and proficiencies do not apply to vessel flight. You use the Piloting Skill much like Ride. Piloting (Fighter) is separate from Piloting (Frigate). A few other skills are around like Navigate and engineering, Knowledge (science).
3) Flight is just for a short couple of adventures or a few special uses. Piloting works for any and all vessels, Engineering is the only other new skill. Sense Direction work instead of Navigate etc.