Hot air balloons rise because the heated air is less dense and therefore lighter than the surrounding air. But hot air balloons need oxygen for their burners to work – and the higher they rise, the thinner the air and the less oxygen available. The all-time record for hot air balloons is about 20,000 meters – or roughly 65,000 feet – set in 1988 by Per Lindstrand of the United Kingdom.
The record for helium balloons is even more impressive. Helium balloons rise because helium is lighter than the surrounding air. As a helium balloon gains altitude, the helium inside expands and becomes less dense, thus enabling the balloon to continue rising. The current altitude record for a helium balloon was set by Malcolm Ross, who flew to over 35,000 meters – or over 113,000 feet – on a balloon launched from an aircraft carrier.