On what date did the first free human flight in a hot-air balloon occur?

The first free human flight in a hot-air balloon occurred on 21 November 1783.

Jean-François Pilâtre de Rozier and François Laurent d’Arlandes made the flight in Paris in a balloon designed by the Montgolfier brothers. It rose from the grounds of the Château de la Muette and traveled roughly 9 kilometers in about 20 minutes.

This was a free flight, meaning the balloon was not attached to the ground by a tether. Earlier demonstrations had used unmanned balloons, and a later animal flight had shown that living passengers could survive aloft. The 21 November journey proved that people could travel through the air in a hot-air balloon.

King Louis XVI had initially considered using condemned prisoners as test passengers, but the plan was rejected. The historic flight helped begin human aviation more than a century before powered airplanes. Balloons still depend on the same basic principle: heated air inside the envelope is less dense than the cooler surrounding air.