How to make a hot air balloon out of paper ?
Without fire, easily.

Without flame.
Out of paper.
Out of tissue paper.

Out of plastic bag.
Out of paper bag.

Paper ?
Paper lantern.

Plastic bag project.

How to make a hot air balloon that really flies ?
Science.

Hot air balloon that flies. A hot air balloon that can fly.
Using paper, using plastic.

Using a hair dryer :
With paper, with tissue paper.
With plastic bags.

Hot air balloon with balloon, balloon without fire.

How to make a hot air balloon ? 
A hot air balloon you can fly in.