Which two brothers invented hot air balloons?

Joseph-Michel Montgolfier (26 August 1740 – 26 June 1810) and Jacques-Étienne Montgolfier (6 January 1745 – 2 August 1799) were paper manufacturers from Annonay, in Ardèche, France best known as inventors of the Montgolfière-style hot air balloon.

Of the two brothers, it was Joseph who was first interested in aeronautics; as early as 1775 he built parachutes, and once jumped from the family house. Joseph then built a box-like chamber 1×1×1.3 m (3 ft by 3 ft (0.91 m) by 4 ft) out of very thin wood and covered the sides and top with lightweight taffeta cloth. He crumpled and lit some paper under the bottom of the box. The contraption quickly lifted off its stand and collided with the ceiling.

Joseph recruited his brother to balloon building by writing, "Get in a supply of taffeta and of cordage, quickly, and you will see one of the most astonishing sights in the world." The two brothers built a similar device, scaled up by three (so 27 times greater in volume). On 14 December 1782, they did their very first test flight, lighting with wool and hay, and the lifting force was so great, that they lost control of their craft. The device floated nearly two kilometers (about 1.2 mi) and was destroyed after landing by the "indiscretion" of passersby.