# eli5 How can planes fly at much higher altitude than helicopters?

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eli5 How can planes fly at much higher altitude than helicopters?

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Planes use wings to generate lift, which is a force that opposes the weight of the plane and keeps it in the air. The wings are designed to be very aerodynamic, which means they can cut through the air more easily. This allows planes to fly at high speeds and high altitudes with relatively little resistance from the air.

Helicopters use rotors to generate lift. The rotors are not as aerodynamic as wings, which means they create more drag as they move through the air. This makes it more difficult for helicopters to fly at high speeds and high altitudes.

In addition, planes are powered by jet engines, which are designed to work more efficiently at high altitudes. Jet engines use the air around them to create thrust, which is a force that propels the plane forward. At high altitudes, the air is less dense, which means it creates less resistance to the jet engines. This allows the engines to work more efficiently and generate more thrust.

We calculate lift (the force that allows us to fly) through several factors. The 3 main ones for this problem are velocity of the airflow, density of the air, and surface area of the wing. Helicopters achieve lift by pushing multiple small thin wings through the air very fast. We can only move those blades so fast through the air and we can’t really change their surface area because bigger blades are harder to spin faster. So the max lift a helicopter can make is closely tied to the density of the air. As elementary science teaches us, as we go up in altitude, the density of air decreases.

Airplanes on the other hand achieve their lift by pushing large wings through the air at relatively slower speeds. This means we can increase lift by going faster or by designing bigger wings. Thus an airplane has more options to adapt to the less dense air at altitude.