Jax asked us this on a flight: "How does something this heavy stay up?" An airplane can weigh as much as 400 cars. It's a fair question.
The Four Forces of Flight
Every airplane in the sky is being pushed and pulled by four forces at the same time:
1. Lift
This is the force that pushes the plane UP. It comes from the wings! Airplane wings have a special shape called an airfoil — they're curved on top and flatter on the bottom. When air flows over the wing, it moves faster over the curved top than the flat bottom. This creates lower pressure above the wing and higher pressure below it, which pushes the wing (and the whole plane) upward.
Try this at home: Hold a piece of paper near your mouth and blow across the top of it. The paper rises up! That's lift in action.
2. Weight (Gravity)
This is the force pulling the plane DOWN toward the ground. It's just gravity! For the plane to fly, lift must be stronger than weight.
3. Thrust
This is the force pushing the plane FORWARD. It comes from the engines! Jet engines suck in air, mix it with fuel, burn it, and blast hot gas out the back — pushing the plane forward really fast. Some smaller planes use propellers instead.
4. Drag
This is the force pushing BACK against the plane, slowing it down. It's caused by air resistance — the air pushing against the plane as it moves through it. Airplanes are designed with smooth, sleek shapes to reduce drag.
How Does a Plane Take Off?
1. The engines create thrust, pushing the plane down the runway faster and faster.
2. As the plane speeds up, air flows over the wings faster, creating more lift.
3. When the lift is strong enough to overcome the plane's weight, the pilot pulls back on the controls and the nose tilts up.
4. The plane rises into the air!
Most big jets need to reach about 150-180 miles per hour before they can take off. That's almost three times faster than a car on the highway!
How Does a Plane Stay Up?
Once in the air, the engines keep providing thrust, the wings keep creating lift, and the pilot adjusts the controls to keep everything balanced. A plane can fly at over 500 miles per hour and as high as 7 miles above the ground — that's higher than Mount Everest!
How Does a Plane Turn?
Planes don't have steering wheels like cars. Instead, they use special moving parts on their wings and tail:
- Ailerons on the wings tilt the plane left or right (called rolling).
- The rudder on the tail swings left or right (called yawing).
- Elevators on the tail pitch the nose up or down.
How Does a Jet Fly?
Jet engines work differently from propellers. A jet engine sucks in air through the front, compresses it, mixes it with fuel, and ignites it. The burning gas expands and blasts out the back at incredible speed — this is what pushes the plane forward (Newton's third law: every action has an equal and opposite reaction).
Modern jet engines are called turbofans. They have a huge fan at the front that moves a lot of air around the outside of the engine — this "bypass" air provides most of the thrust and makes the engine quieter and more fuel-efficient. The engines on a Boeing 777 are so powerful that each one produces as much thrust as 100,000 horsepower!
Propeller planes work differently — a motor spins a propeller, which pulls air backward and pushes the plane forward. They're slower but more efficient for short flights. You can learn about both types in our guide to types of airplanes.
How Fast Do Airplanes Fly?
Most commercial jets cruise at about 500-575 miles per hour (Mach 0.78-0.85). That's about 85% of the speed of sound! Here are some comparisons:
- Car on the highway: 70 mph
- Fastest train: 250 mph
- Commercial jet: 550 mph
- Speed of sound: 767 mph
- Concorde (retired): 1,354 mph (twice the speed of sound!)
Planes fly faster at higher altitudes because the air is thinner — less drag slowing them down. That's why jets climb to 35,000 feet.
How High Do Airplanes Fly?
Most commercial jets cruise at 31,000-42,000 feet — that's about 6-8 miles above the ground, higher than Mount Everest (29,032 feet). At that altitude, the air temperature outside is about -60°F and there's barely enough oxygen to breathe. That's why the cabin is pressurized — the air inside the plane is kept at a comfortable level, like being on a mountain about 6,000-8,000 feet high.
Fun Fact
The longest non-stop flight in the world is from Singapore to New York — it takes about 18 hours and covers over 9,500 miles. We wrote more about it in the longest flights in the world.