How do hot air balloons fly and how do you steer them?

Credit: ITV News West Country

Hot air balloons work on a simple principle - hot air rises while cold air sinks.

This means the balloons fly because the hot air inside weighs less than the air on the outside - causing it to float upwards.

Here's a how to guide of all you need to know...

It's ok! This one's on the way up, it's being prepared for flight. Credit: ITV News West Country


  • ENVELOPE: The fabric balloon which holds the air

  • BASKET: Where the pilot and passengers stand

  • BURNERS: The instrument used to heat the air in the envelope.

  • PARACHUTE VALVE: A circle of fabric cut out of the top of the envelope controlled by a chord in the basket.

Credit: ITV News West Country


When a pilot wants to make the balloon rise they turn on the burner, which makes the air inside the envelope hotter. The hotter the air, the less it weighs, the quicker the balloon will rise.

When they want to go down, pilots either let the air cool naturally, or to speed up the process, let hot air out of the balloon by opening the parachute valve.

To keep the balloon at a stable level the pilot must use the burner at regular times during the flight to ensure the right amount of hot and cold air are present inside the envelope.

The burner is in regular use during flights to keep the mix of hot and cold air just right. Credit: ITV News West Country


Technically, a pilot is at the mercy of the wind when it comes to flying a hot air balloon, BUT there are a few things they can do to aid their travel.

By moving the balloon up or down, the pilot can move the balloon left or right as well. This is because the wind blows in different directions at different altitudes.

So if a pilot wants to go east, they move up or down to find the easterly wind, and then follow the current.

There is also a green and black cable in the basket itself, which helps to turn the basket to face the direction of travel.

  • Still confused? We asked pilot Ian Martin to explain: