Balloon (aeronautics) balloon filled with hydrogen would be able to rise in the air. The first recorded manned flight was made in a hot air balloon built by the Montgolfier brothers on 21 November 1783. The flight started in Paris and reached a height of 500 feet or so. The pilots, Jean-François Pilâtre de Rozier and François Laurent d'Arlandes, covered about 5½ miles in 25 minutes. On 1 December 1783, Professor Jacques Charles and the Robert brothers made the first gas balloon flight, also from Paris. Their hydrogen-filled balloon flew to almost 2,000 feet (600 m), stayed aloft for over 2 hours
Hot air balloon basket-less balloons (called "Hoppers" or "Cloudhoppers") have as little as of envelope volume; for a perfect sphere the radius would be around . At the other end of the scale, balloons used by commercial sightseeing operations may be able to carry well over two dozen people, with envelope volumes of up to . The most-used size is about , and can carry 3 to 5 people. The top of the balloon usually has a vent of some sort, enabling the pilot to release hot air to slow an ascent, start a descent, or increase the rate of descent, usually for