How do airplanes actually fly?
A little curiosity. Four forces. A whole new perspective.
Recognize the four forces and describe how a wing interacts with moving air.
Start with the air
An airplane moves through a fluid: air. Its wings turn the surrounding airflow and create pressure differences. The resulting aerodynamic force has a component called lift, perpendicular to the relative airflow.
Four forces, one airplane
Lift, weight, thrust and drag act together. In steady, level, unaccelerated flight, lift balances weight and thrust balances drag. Changing those relationships changes the motion.
Try a mental experiment
Imagine putting your hand into a moving stream of water and changing its angle. You can feel the fluid push differently. Wings also interact with a moving fluid, although the details of wing geometry and airflow matter.
Check your understanding
Which force opposes the motion through the air? Drag. Continue to the next lesson to explore all four forces.
Ready for a knowledge check?
Try a related five-question challenge with explanations after every answer.
Test your understandingThe four forces of flight
Sample lesson · Editorial review pending. Educational introduction, not flight instruction.
Further reading: FAA handbook