How Does a Hot Air Balloon Fly?

Whether it’s a romantic trip to the skies for two or a chance to let the whole family sightsee, a hot air balloon ride sounds like just what you’re looking for. You’ve never ridden in a hot air balloon, so you have some questions. Namely, how does the balloon fly?

Heat rises, so the hot air within the balloon has less density than the cool air, allowing the balloon to ascend. Due to the principles of buoyancy, or the upward exertion of the air, the hot air balloon can remain hundreds, sometimes thousands of feet up until the pilot brings the balloon down for a landing. 

In this post, we’ll talk in far more detail about how hot air balloons fly. We’ll also discuss the average height a hot air balloon travels, what kind of speed you should expect when flying, and whether you move quickly in a balloon.  

The Parts of a Hot Air Balloon

We haven’t covered hot air balloons on the blog in a while, so let’s start this post by going over the parts of a hot air balloon. This information is also handy for first-time balloon riders. 


Although it’s called a hot air balloon, the technical name of the balloon isn’t that at all. Instead, this part is known as the envelope. The envelope features several components within it, such as the tapered bottom, which is referred to as the skirt. The top of the balloon is appropriately named the crown.

The envelope is rarely one piece, but rather, several panels attached. The technical name for each panel is the gore. The fabric used for the panels is a ripstop nylon that’s fire-resistant so you don’t have to worry about the hot air balloon accidentally going up in flames. If you’ve ever used a mountaineering or hiking backpack, it’s made of the same type of fabric.

The average hot air balloon or envelope will have 24 gores altogether. A type of webbing known as load tapes as well as stitching keeps the gores attached. The load tapes are like the material featured in car and truck seatbelts, so you know it’s good stuff. This webbing limits strain on the gores and keeps the balloon weight upward.

Envelopes also feature a coating of polyurethane with ultraviolet inhibiting so the material won’t fade in the sun. 

The crown of the balloon includes an electrical sensor known as a pyrometer. This meter reads the air temperature, which is not to exceed a certain limit. If the air temperature gets too high, then the strength of the hot air balloon’s ripstop fabric could degrade. 


The second part of a hot air balloon is the burner, which is where the heated air that powers the balloon comes from. We’ll talk more about that heated air in the next section, so make sure you keep reading. 

Some hot air balloons have only one burner and others two, with the need for a second usually dependent on the size of the balloon. The burner, be it one or two, will aim up at the middle of the hot air balloon. A pilot light activates the burner(s) through the blast valve. The balloon captain can use the blast valve to send more fuel to the burner tanks or less, such as for landing. All the pilot has to do is adjust a trigger.


Last but certainly not least is the basket, also referred to as the gondola. This is where you and your loved ones sit when on a hot air balloon ride. Some baskets are still made of wicker, but you’re just as likely to see very durable materials such as fiberglass or aluminum. 

The basket features a framework that’s connected to the stainless steel cables over your head. There may be as many as 24 cables that attach the basket to the balloon.

The purpose of this framework is multiple. The framework keeps the basket stable, especially when you land, so you don’t have to worry as much about the basket tipping. That’s not to say it can’t happen, but it’s less likely. The framework also safeguards the burner system and keeps passengers safe when riding.  

Colorful hot air balloon early in the morning in Hungary

How Does a Hot Air Balloon Fly?

Now that you’re better acquainted with the parts of a hot air balloon, let’s discuss how the balloon flies, as it’s very fascinating stuff! 

The burner system is integral to allowing a hot air balloon to fly. The gas that fuels the burner system is liquid propane. The pressure between the burner and fuel tank sends the gas to the pilot light, where it’s ignited. The burner system features a pressure gauge as well so the balloon pilot can always keep an eye on how much pressure the hot air balloon gets.

In a multi-burner system, a hose can send the propane from one burner tank to the second. The burner also has coils so the liquid gas will vaporize when it hits the coils. The pilot light then kindles the vapor using the blast valve. The resulting flame is anywhere from six to eight feet tall. That flame rises into the envelope.

The amount of heat from this ignition is significant, at least 12 million British thermal units or BTUs an hour. When the vapor is alight, you’ll definitely hear it in the form of a whoosh sound. 

The air within the envelope becomes very warm, which goes back to what we mentioned in the intro. Heat rises, which means the hot air in the envelope is higher than the cold air, which naturally sinks. The hot air is less dense and provides the necessary ascension for the hot air balloon. 

This means that, outside of the initial burst of hot air from the burner system, the air within the envelope must stay warm so you can continue flying. The balloon pilot can warm the air in the envelope in one of two ways.

The first method is through a metering valve, also known as a cruise valve. The balloon pilot will watch how much propane is traveling to the burner to ensure the burner output remains consistent. If it does, then the air temperature within the envelope should be consistent too, staying warm enough for a prolonged flight. 

The balloon pilot can also use the blast valve, which provides the abovementioned 12 million BTUs of heat. After the initial blast, powering on the blast valve periodically to reheat the air in the envelope will also maintain the temperature. The better the temperature consistency, the smoother the altitude when you fly. 

How High Can You Fly in a Hot Air Balloon?

Speaking of altitude, how high can you expect to fly when hot air ballooning with friends or family? We’re glad you asked! This is a topic we’ve delved into on the blog, so let’s recap that information here.

The lowest altitude we’ve seen for hot air balloon flights is 500 feet, but expect that you’ll be at least 1,000 feet up. In some instances, you’ll be as high as 3,000 feet in the air. This is pretty high, as skyscrapers that broke the 3,000-foot height barrier were considered the tallest in the world just a few years ago. 

You’ll definitely be able to enjoy the sights that high up, but don’t expect to go too much higher than 3,000 feet. At around 8,000 feet, the air quality changes, thinning out. What could follow is altitude sickness, which might cause symptoms like breathing difficulties, nausea, and headaches, none of which would make ballooning very fun!

Plus, there’s also the little fact that as you ascend every 1,000 feet higher, the temperature decreases by as much as 4 degrees. You don’t want to be too cold when hot air ballooning, as this also impacts your enjoyment of the experience.  

So what dictates your hot air ballooning height? Is it the balloon company you book through? That could be part of it, but your max height mostly has to do with the weather. You need some wind when ballooning, typically between 4 and 6 miles per hour, but if the winds are closer to 12 MPH, then it’s no longer safe to fly. 

How Fast Do Hot Air Balloons Fly?

Riding in a hot air balloon is not like taking a spin in a racecar. It’s not even akin to parasailing, which features speeds upwards of 30 MPH. Ballooning is one of the most leisurely activities you can do in the sky. Your balloon pilot will guide you along at about 5 MPH. In some instances, you may go only marginally faster, like 8 MPH, but it’s nothing nerve-wracking. 

The low speed makes hot air balloon rides appropriate for kids and adults alike. 

Final Thoughts

Hot air balloons include a burner system that ignites propane to send the balloon into the air. By keeping the temperature in the balloon warm, it will stay buoyant so you can float lazily by and drink in the beauty of the world at 1,000+ feet. We hope the information in this article has inspired you to try hot air ballooning! 

Geoff Southworth

I am a California native and I enjoy all the outdoors has to offer. My latest adventures have been taking the family camping, hiking and surfing.

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