A hot air balloon is a type of aircraft that uses hot air to rise and travel. It is also known as a hot balloon, airship, or aerostat. Another word for hot air balloon is a sky lantern, which is often used in celebrations and festivals. Some other synonyms for this amazing flying machine include gas balloon, free balloon, or envelope. People also refer to it as a hot airship or a fire balloon. No matter what you call it, a hot air balloon is a wonderful invention that allows us to soar high in the sky with a breathtaking view of the world below.