A gas balloon is any balloon that stays aloft because it is filled with a gas less dense than air or lighter than air (such as helium or hydrogen). A gas balloon may also be called a Charlière for its inventor, the Frenchman Jacques Charles. Today, familiar gas balloons include large blimps and small rubber party balloons. Blimps have displaced zeppelins (which are not balloons) as the dominant form of airship.
The first gas balloon made its flight in August 1783. Designed by professor Jacques Charles and Les Frères Robert, it carried no passengers or cargo. On 1 December 1783 their second hydrogen-filled balloon made a manned flight piloted by Jacques Charles and Nicolas-Louis Robert, 10 days after the first manned flight in a Montgolfier hot air balloon.
The next project of Jacques Charles and 'Les frères Robert' was La Caroline, an elongated steerable craft that followed Jean Baptiste Meusnier's proposals for a dirigible balloon, incorporating internal ballonnet (air cells), a rudder and a method of propulsion. On September 19, 1784 the brothers and M. Collin-Hullin flew for 6 hours 40 minutes, covering 186 km from Paris to Beuvry near Béthune. This was the first flight over 100 km.
Gas balloons remained popular throughout the age before powered flight. They could fly higher and further than hot-air balloons, but were more dangerous as they were usually filled with hydrogen gas (which, unlike helium, could be easily mass-manufactured). Gas balloons were used in the American Civil War by Thaddeus Lowe. They were used in the Napoleonic Wars (to very limited extent), and throughout the 19th century by hobbyists and show performers such as the Blanchards.
Gas ballooning has been popular in Europe, most notably in Germany, using hydrogen as a lifting gas. Several gas balloon clubs exist throughout the country with well organized launch sites and well defined infrastructure making flights relatively easy to do. Rough estimates show 150 active gas pilots in Europe. In stark contrast, gas ballooning in the USA might have at most 30 active pilots who typically fly only once a year at the Albuquerque Balloon Fiesta in October. This is primarily due to the prohibitively high cost of helium (~$8,000 for a single flight as of 2008), the lifting gas that most American pilots must use because of the design of their balloons. This is starting to change with the introduction of hydrogen as a lifting gas, but there are still only a handful of hydrogen-rated balloons in the country. The German gas community has been a valuable resource in helping the US pilots gain skills in flying gas balloons and working with hydrogen as a lifting gas. Many US gas pilots have been and are currently participating in training flights in Germany.
A gas balloon can also be tethered. Aerophile is the world's largest lighter-than-air carrier, flying 300,000 passengers every year through its four operations in Paris, Disneyland Resort Paris, Walt Disney World and Orange County Great Park.
The altitude record for a manned balloon flight was set at 39.045 kilometers on October 14, 2012 by Felix Baumgartner breaking a record of 34.7 kilometers on May 4, 1961 by Malcolm Ross and Victor Prather in a balloon launched from the deck of the USS Antietam in the Gulf of Mexico.
The altitude record for an unmanned balloon is 53.0 kilometers. It was reached by a Fujikura balloon with a volume of 60 thousand cubic metres, launched in May 2002 from Sanriku, Iwate, Japan. This is the greatest height ever obtained by an atmospheric vehicle. Only rockets, rocket planes, and ballistic projectiles have flown higher.
On other planets 
The Russian space probes Vega 1 and Vega 2 each dropped a helium balloon with scientific experiments into the atmosphere of Venus in 1985. The balloons first entered the atmosphere and descended to about 50 km, then inflated for level flight. Otherwise the flight was uncontrolled. Each balloon relayed wind and atmospheric conditions for 46 hours of a possible 60-hour electric battery power budget.
See also 
- Gordon Bennett Cup - famous long-distance gas balloon race
- Tethered helium balloon
- Double Eagle II - first manned balloon to cross the Atlantic Ocean
- Larry Walters - used a lawn chair and 45 helium-filled weather balloons to rise to 16,000 feet (4,900 m)
- Sky anchor
- Five Weeks in a Balloon by Jules Verne
- Federation Aeronautique Internationale, Ballooning Commission, Hall of Fame, Robert Brothers.
- Fiddlers Green, History of Ballooning, Jacques Charles
- Science and Society, Medal commemorating Charles and Robert’s balloon ascent, Paris, 1783.
- Eccentric France: Bradt Guide to mad, magical and marvellous France By Piers Letcher - Jacques Charles
- Biographical dictionary of the history of technology, Volume 39 By Lance Day, Ian McNeil. Charles, Jacques Alexandre Cesar
- Federal Aviation Administration - F.A.Aviation News, October 2001, Balloon Competitions and Events Around the Globe, Page 15
- Nicholas Piantanida, while attempting to set a new skydiving jump record, is claimed to have reached 123,800 feet (37.73 km) on February 2, 1966. Piantanida was unable to disconnect his breathing apparatus from the gondola, so the ground crew jettisoned the balloon at the flight ceiling. The flight did not set a flight record because he descended without the balloon. See excerpts from Craig Ryan's description of Piantanida's flight and harrowing descent: Tim Baggett. "QinetQ Flight". Retrieved 2009-12-29.
- Saito, Y; et al. (00/2006). "Development of a 2.8 µm film for scientific balloons". Advances in Space Research (ELSEVIER) 37 (11): 2026–2032. Bibcode:2006AdSpR..37.2026S. doi:10.1016/j.asr.2005.05.053.
- Gasballoon Launch field Gladbeck World modern Gasballoon Launch field in Germany
- Albuquerque Gas Ballooning Association Hosts of the America's Challenge Gas Balloon Race
- Gas Ballooning.net - current information on the state of sport gas ballooning by gas balloon pilot Brian Critelli from Texas, USA.
- Gas Ballon.be - Belgian site with good gas balloon competition information
- Stratocat - Historical recompilation project on the use of stratospheric balloons in the scientific research, the military field and the aerospace activity