How do hot air balloons work?

We all love experiencing a thrill and in recent years, travel and tourism has enabled people from across the world to not only visit new places but try activities they have never done before. In the UK or abroad, there is so much to keep you entertained - from paddle boarding in the sea to hikes on land or taking to the sky in a hot air balloon.

But how do hot air balloons work? And who invented them?

Here, BBC Bitesize takes a closer look at the history of hot air balloons, how they have evolved over time and the science behind how they take flight. Find out more below!

A hot air balloon is a lighter-than-air aircraft that floats in the sky, usually carrying passengers. They consist of three components – a huge fabric bag, known as an envelope, an open-flame burner which acts as the engine and a basket to hold the passengers on the ride.

This unique aircraft is filled with heated air which enables the balloon to rise. The aircraft gains its lift as the envelope contains warmer, less dense air than the cooler air surrounding it.

Over time, many hot air balloons have taken flight around the world and been at the centre of famous novels and films. One notable example is the hot air balloon in the Wizard of Oz owned by the Wizard himself.

The earliest form of human flight was the hot air balloon. But how long have they been around?

Air transport has changed significantly through the decades, but the first hot air balloon was invented in France by the Montgolfier brothers in 1783. Joseph-Michel and Jacques-Étienne Montgolfier had first launched an unmanned paper balloon in their hometown of Annonay in June that year.

And prior to human flight, in September 1783 they tested their invention with the first living passengers - a sheep, a duck and a rooster. The animals were sent up in a tethered balloon at Versailles in an event staged before King Louis XVI and Queen Marie Antoinette.

On 21 November 1783, the first free (non-tethered) human flight took place and saw Jean-François Pilâtre de Rozier and François Laurent, Marquis d’Arlandes fly above Paris. Today, hot air balloons are used less for travel and more for tourism, events and recreational sport.

As mentioned earlier, a hot air balloon consists of three components – the envelope, burner and basket. But if you’ve ever wondered how they actually work, we’ve put together a quick, more basic explanation of how most hot air balloons take riders to the sky.

Scientifically speaking, warmer air rises in cooler air as it is less dense, as it has less mass per unit of volume. Hot air is less dense than cold air, making it more buoyant (able to float).

Before take-off, the envelope of the hot air balloon is partially filled with cold air. When it starts to form its usual, firmer shape, the burner is fired up to heat the air to create the lift.

The burner is like the engine of the balloon and the heat from the burner expands the air inside the balloon. Most hot air balloons heat the air by using propane.

Heating the air inside the balloon causes the molecules to bounce and spread out. Heating the air causes it to expand, making it less dense than the surrounding air. It becomes lighter than the cooler air outside and causes the balloon and attached basket to rise.

If the air is cooled, it will enable the balloon to slowly descend. The hot air balloon basket usually carries passengers and is attached to the bottom of the envelope with strong cables.

As you can imagine, hot air balloons can reach incredible heights. But how high can a hot air balloon go?

Well, this varies depending on source, but most state that hot air balloons usually fly between 500 and 5000 feet above ground. According to Guinness World Records, it was Dr Vijaypat Singhania who achieved the altitude record of 21,027 m (68,986 ft).

The ascent took place on 26 November 2005 in Mumbai, India, in a Cameron Z-1600 hot-air balloon.

Unlike cars, boats or aeroplanes, you can’t steer a hot air balloon in a traditional sense as they don’t have a steering wheel, engine or rudders. Instead, pilots navigate hot air balloons by changing the altitude, accessing different wind layers that often blow in different directions and speeds.

When flying, skilled pilots change the direction of the hot air balloon by burning (to go higher up) or allowing air to cool (to go lower), catching different winds at different heights. When it comes to landing, the balloons gradually release hot air to descend.

But because they can’t be steered, they don’t have pre-decided landing locations like aeroplanes do. Usually, companies have safe fields to land on and are tracked by crew members who follow their descent.

Hot air balloons have grown in popularity in recent decades, with locations across the world offering an opportunity to tick off the ‘bucket list’ moment. When it comes to travel, excursions or adventure-seeking activities in general, there is always some form of risk involved.

But how safe are hot air balloons? Well, the short answer is they are very safe, more often than not, with rides rarely being fatal.

But while accidents are very rare, they do happen. Like with any air travel or activity, there is never zero risk and there are always factors like weather,strict regulations and more to consider.

Through time, regulations surrounding hot air balloon rides have changed and more could follow in the future to ensure even more safety. Before going in a hot air balloon, it is very important to research the activity, those who are offering it and prepare for your safety as much as possible.

Back in 1784, Scottish aviator James Tytler became the first in the UK to fly a hot air balloon, making a flight over Edinburgh. Today, there are still opportunities to see hot air balloons in the UK, as part of tourism activities and events.

Among the most famous is the Bristol International Balloon Fiesta, which is Europe’s largest free hot air balloon festival. Held since 1979, every year thousands attend to watch over 100 balloons take to the sky.

When is the Bristol hot air balloon festival?

In 2026, the Bristol International Balloon Fiesta takes place between 7 August and 9 August and is a free to attend three-day event. It is held in the rolling hills of Ashton Court Estate on the outskirts of Bristol city centre.

This article was written in May 2026

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