Airplanes stay in the air because their wings generate lift as they move forward, and airplanes must move forward to maintain their lift.
Or to put it another way, lift is an upward, vertical force that pushes against a plane’s weight and keeps it in the air.
While it’s theoretically possible for an airplane to stay perfectly still in the air, it’s unlikely in reality.
A plane that stays completely still in the air would have no lift and fall down.
Pilots take off by increasing their forward thrust to generate lift, letting the plane rise.
Pilots also steer planes by using a complex system of ailerons, elevators, and a rudder to control the plane’s direction.
How Airplanes Stay in the Air Without Falling
Airplanes stay in the air without falling by manipulating the four forces acting on them.
These four forces are:
Lift pushes the airplane vertically upwards.
Lift is generated from air moving over the plane’s wings.
Weight pushes the airplane downwards.
An airplane maintains altitude when its weight equals its lift.
Thrust moves the airplane horizontally forward.
An airplane’s engine provides its thrust.
Drag moves the airplane horizontally backward.
An airplane’s thrust must exceed its drag to move forward horizontally.
To cruise, the plane’s pilot will ensure thrust is higher than drag and that the plane’s lift and weight are equal.
The pilot will reduce both thrust and lift to lower the plane to descend.
Planes Can Technically Stay in the Air Without Moving
It’s theoretically possible for aircraft to stay in the air without moving.
For a plane to stay in the air without moving, the 2 sets of opposing forces must equal each other – i.e., lift must equal weight, and drag must equal thrust.
In reality, it’s extremely rare for this to happen, and a plane could only last a few seconds in the air without moving.
As an airplane can’t generate lift if it’s stationary, it needs to move forward to stay in the air.
So, a plane that stays still in the air would fall from the sky due to lack of lift.
How Planes Take Off
A plane’s engine accelerates the aircraft to high speed, causing airflow over its wings.
A plane’s wings experience lift when the air moves over its wings to the ground.
Lift allows a plane to move upwards, while thrust moves it forwards.
The combination of moving fast horizontally and vertically lets a plane take off.
Related: How Fast Does a Plane Go to Take Off?
How Planes Land
Airplanes land by reducing their thrust and lift in order to descend.
The plane’s wings change shape to make the plane less aerodynamic, which increases drag and decreases lift.
The plane descends as a result.
The aircraft also changes its pitch to a nose-up position to further reduce lift and let the rear landing gear contact the ground.
Related: Can Autopilot Land a Plane?
How Planes Steer in the Air
Pilots steer planes in the air by using multiple controls, including the plane’s ailerons, rudders, and elevators.
A plane’s ailerons are at the end of the plane’s wings.
This component raises and lowers the aircraft’s wings, which changes the plane’s angle of roll.
Pilots control the ailerons using a control wheel.
A plane’s rudder is the moving part of its tailfin.
The rudder controls the airplane’s yaw, which is its lateral movement around a vertical axis.
The rudder helps steer the aircraft right or left, and it’s operated with a foot pedal.
A plane’s elevators control its pitch.
So adjusting a plane’s elevators decides its angle of climb or descent.
Plane Can Fly Continuously For Over 20 Hours
A commercial plane can fly for more than 21 hours without refueling.
The world’s longest commercial flight without refueling covered 12,427 miles or 20,000 km, and flew for 23 hours.
Small planes and military planes can fly for a much shorter time, usually only a few hours maximum.
How High Do Planes Fly?
Turboprop planes fly as high as 25,000 to 30,000 feet.
Commercial planes fly between 32,000 to 40,000 feet above the ground.
Private planes can fly as high as 50,000 feet.
Fighter planes can fly the highest: 50,000 feet or higher.
- Planes stay in the air by manipulating the forces acting on them.
- Planes can climb by increasing their lift by adjusting their wing’s ailerons.
- Planes can move faster by increasing the thrust from their engines.
- Conversely, planes also decrease the lift acting on them and reduce thrust to slow down and descend.
- An airplane could hypothetically remain still in the air if each pair of opposing forces acting on it were equal. But, this is an extremely unlikely scenario because planes can’t stay in the air without lift.
- Planes can climb by increasing their thrust and adjusting their wings to increase lift.
- The combination of increased forward movement and rising lift lets a plane take off from the ground.