The Differences Between Gas Balloons and Hot Air Balloons Gas and hot air balloons share a number of similiarities. The part of the balloon that holds the hot air or gas is called the envelope. The part of the balloon that carries passengers is called the gondola, or basket. The differences between the two types of balloons range from cost and flight duration to passenger load and lift. Hot air balloons fly as a result of a hotter air temperature inside the envelope than outside.
Hot air rises.
Enough hot air will gently lift the envelope, gondola and passengers into the sky. The ideal time for balloons to fly is typically in the morning , when the cooler temperatures and lower winds provide a better environment for flying. Balloonists prefer winds to be twelve miles per hour or less. Gas balloons fly as a result of a lifting gas in their envelopes . In the United States pilots fly with helium or hydrogen as the lifting gas.