Which balloon is filled with hot air?

In aeronautics, a balloon is an unpowered aerostat, which remains aloft or floats due to its buoyancy. A balloon may be free, moving with the wind, or tethered to a fixed point. It is distinct from an airship, which is a powered aerostat that can propel itself through the air in a controlled manner.

The hot air balloon or Montgolfière obtains its buoyancy by heating the air inside the balloon; it has become the most common type. The first balloon which carried passengers used hot air to obtain buoyancy and was built by the brothers Josef and Etienne Montgolfier in Annonay, France in 1783: the first passenger flight was 19 September 1783, carrying a sheep, a duck, and a rooster. Montgolfière balloons are relatively inexpensive, as they do not require high-grade materials for their envelopes, and they are popular for balloonist sport activity.