Can I use normal air instead of helium when building a blimp?

Check your local and state laws regarding aerospace vehicles and FAA and EAA for blueprints and advice. Draw up a plan and purchase the required materials and tools, helium cylinders...

A blimp is a safer, slower version of a plane. If a motor fails, the blimp fill not crash land. But since blimps use helium, they are very expensive.

You can if you have a refrigerant dehumidifier that is connected to your central air system. Otherwise, you'll need to use a portable dehumidifier to remove moisture from the air.

Yes, helium tanks can be dangerous if they aren’t handled correctly, since they contain compressed gas. For this reason, it’s very important to recycle or dispose of them properly.

It’s not clear that Party City recycles tanks. You can call your local Party City to find out about their policy.

You will probably have to take your tanks to your local recycling center or hazardous waste disposal site.

You can, it just won't be as flexible when you fold it. I'd recommend not adding stems, as that will put more weight on your flowers.

I don't think you should use a cast iron pan but it could work if you are desperate. I would definitely use a gas stove.

Yes, it really doesn't matter.

Yes, just use one that doesn't have any designs on it, as that will improve the look. For example, I made cat ears using a tan-colored headband, and nobody can...