Which two layers of the atmosphere do virtually all aircraft fly through?

The troposphere and stratosphere are the two layers of the atmosphere that virtually all aircraft operate within. The troposphere is the lowest layer of the Earth's atmosphere and extends from the surface up to approximately 8 to 15 kilometers (5 to 9 miles). This layer contains most of the atmosphere's mass, including clouds, weather phenomena, and is where commercial airliners typically fly.

Above the troposphere lies the stratosphere, which extends to about 50 kilometers (31 miles) above the Earth. This layer is known for its relative stability and a gradual increase in temperature with altitude due to the presence of the ozone layer, which absorbs and scatters ultraviolet solar radiation. Most commercial and many private aircraft will climb into the lower part of the stratosphere to avoid weather and turbulence that occurs in the troposphere.

The other layers mentioned—mesosphere, thermosphere, and exosphere—are not typically accessed by commercial aircraft. The mesosphere extends above the stratosphere and is where meteors burn up upon entering the atmosphere. The thermosphere is characterized by a dramatic rise in temperature and altitude, while the exosphere is the outermost layer that gradually fades into space. Aircraft do not operate in these