How to hang foil balloons from ceiling
Venue decoration with mylar balloon stars and moons
If I want to hang foil stars from the ceiling, do I fill them with air or helium? And can I use fishing wire to attach them to the ceiling?
You would fill them with air, and then use either fishing line (monofilament) or ribbon in matching colors to attach them to the ceiling.
Unless there's already a bunch of hooks in the ceiling, you also need a way to attach the strings to it.
Some ceilings have metal structures. In this case, use Clik-Clik magnets or similar magnets with a ring or hook.
Alternatively, try removable command hooks as a way to attach the foil balloons to the ceiling.
If the venue owner doesn't want you to attach anything to the ceiling, then you could fill the balloons with helium and have them float up to the ceiling.
The drawback with this solution (apart from the cost for helium) is that you cannot arrange the balloons as you'd like.
I've added more examples of balloons hanging from the ceiling that you may want to check out.
Hope that helps!