How Do Airplanes Fly?

Explore the Miracle of Flight

Although we weren’t born with wings, humans have been obsessed with flying for thousands of years. Even Leonardo DaVinci, who was born in 1452 and became famous for his artistry (including painting the Mona Lisa) dreamt of taking flight. He wrote more than 35,000 words and drew 500 sketches focused on flying machines, the nature of air, and bird flight.

Over the course of human history, flight is everywhere. Mythology placed gods in the sky, folklore had a man on the moon, and the modern world is full of superheroes that possess the power of flight, from Ironman to Captain Marvel.

Of course, today, flight isn’t just a dream, it’s a part of our everyday modern life. But just how do airplanes fly? And how far can we push the limits of what airplanes are capable of, from how heavy they can be, to how fast and high they can go? Let’s go over a few awesome facts!

The Science of Flight: Understanding Air Pressure

So just how do airplanes stay up in the sky?

When learning how airplanes can take to (and stay in!) the sky, the first thing that we need to know is that the air that planes fly through has weight.

And while many people may think air and oxygen are the same thing, they’re actually different! In fact, air is made of different gases: oxygen, carbon dioxide and nitrogen. The molecules of air are always moving around, and this movement creates ‘air pressure.’

The amazing discovery of air pressure was made by Evangelista Torricelli in 1604. When experimenting with measuring mercury, he discovered that air put pressure on the mercury.

Today, you can see the impact of air pressure, and the ‘weight’ it can apply, when you think of hot air balloons. When the air inside the balloon is hot, the movement of the molecules expands and the air becomes lighter than the cool air around it, causing the balloon to rise up. But when the air inside the balloon cools, the movement shrinks and the air becomes more dense, making the balloon sink back down.

The Secret to How Airplane Wings Work

The second thing we need to know about the miracle of flight is how an airplane’s wings work! They don’t flap like a bird’s, so what’s the deal?

Dynamics of flight airplane wing image
This image shows how airplane wings use a special shape to create lift. Image Credit: NASA

Airplane wings have a special shape that makes the air move faster over the top of the wing. This fast moving air has a special effect on the air pressure we just learned about above. Air that moves faster above the wing is lighter (lower pressure) than the slower moving air below the wing (high pressure). 

It’s this difference in pressure that creates a force on the wings that lift the plane up into the air.

How Fast Do Planes Fly?

As you could imagine, with so many different kinds of planes, from commercial airliners to speedy jets, there is a wide variety in how fast airplanes can fly.

  • Commercial airliner cruises between 925-965 km/h (500 to 521 knots)
  • Military aircraft can exceed 2,400 km/h (1,297 knots)
  • The fastest jet in the world is NASA’s X-43 experimental plane. Thanks to its scramjet design it was able to reach a speed of Mach 9.6, or 11,854 Km/h.

How Much Do Commercial Airplanes Weigh?

Although they seem to fly effortlessly, airplanes can be quite heavy.

According to the National Air and Space Museum, the average commercial airplane (the Boeing 737-800) weighs 41,000 kilograms or 90,000 pounds! But when you add in fuel, passengers, cargo, crew, it can carry a maximum of almost double, or 80,000 kilograms (175,000 pounds).

Put another way, the average commercial flight is heavier than:

  • 22 pickup trucks (3,500kgs each)
  • 13 Male African Elephants (6,000kg each)
  • 6 busses (12,000 kgs each)
  • 2.6 humpback whales (30,000kgs each)

Why Can't Airlanes Fly Into Space?

X-15 aircraft
A photo of the X-15 aircraft. Credit: National Museum of the United States Air Force Museum

Knowing that airplanes can go so high might have you wondering why we don’t fly them right to the moon?

It turns out, there’s a very important reason why we can’t fly an airplane to the stars.

Remember that bit about the role that air pressure plays in flight? 

As you travel higher and higher towards space, the air gets thinner and thinner, meaning the air pressure drops too. Airplanes as we know them need both propulsion (a force moving them forward) and lift (which, as you discovered above, is what air pressure helps to provide).

As planes go higher into the sky, at a certain point the air becomes too thin to provide lift.

According to BBC Science Focus, there are planes that can fly into space, but they’re very different from the airplanes that we think of. One example is first plane to reach space. The X-15 was designed in the mid-1950s. It made its first flight in June 1959, using thin, stubby wings for generating lift and stability while travelling at over five times the speed of sound. It also had a revolutionary form of rocket motor. 

Making Your Own Paper Airplane

As fun as it is to learn the science behind how airplanes fly, it’s even better to experience it in action!

According to Popular Mechanics, paper airplanes have played a big role in helping people to learn about the mechanics of flight. It’s been reported that British engineer and aviator Sir George Cayley made the first folded paper plane to approach modern specifications in the early 1800s as part of his personal experimentation with aerodynamics.

Paper Airplane Plans: The Dart

Follow the instructions below to make your own paper airplane!

Build a paper airplane step 1
Step 1: Fold the paper in half
How to make a paper airplane step 2
Step 2: Unfold and then fold the corners into the center line.
How to build a paper airplane step 3
Step 3: Fold the top edges to the centre.
How to build a paper airplane step 3
Step 4: Now fold the paper airplane in half again
How to build a paper airplane step 3
Step 5: Now fold the wings down to meet the bottom edge of the plane's body. You're done!
Paper airplane ready to launch
Now you're ready to go have some fun experimenting!

A Day Just for Paper Airplanes: National Paper Airplane Day!

Like you needed any excuses to celebrate paper airplanes – there is in fact a very special day for it. On May 26th every year, people celebrate National Airplane Day. 

Celebrate by experimenting with your paper airplane. Try testing:

  • How far can you make your paper airplane fly?
  • How long can your paper airplane stay in flight?
  • What happens if you alter the design? For example making the wings larger or smaller, or even by decorating your plane?

Hint: There’s more than one way to build a plane! There is an awesome variety of paper airplane plans to be found online!

Do you LOVE to Build and Get an Understanding of How Things Work?

If you answered “YES!”, then you have to join us at STEM Camp!

Each summer, our campers join in for a week of themed hands-on activities that allow them to stretch their imaginations and have fun, all while learning about STEM!

Visit our themes page to learn more. 

Join Us Online and Showcase Your Paper Plane Creations!

We’d love to learn how your paper airplane experiment went! 

Follow (@stem_camp) on social media and tag us in photos of your awesome experiment!


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