Lift(carrying capacity), fuel economy, stresses on the air frame, temperature the air frame is exposed to.
Yes, jets are airplanes but they are called supersonic airplanes.
Airplanes had expedited traveling and could travel over any terrain. Land, Sea, Mountain,etc...
Now we have airplanes and cars now
Airplanes need a lot of speed to take off because they are not designed for vertical takeoff and are to heavy to do so.
Averages 370 knots
They eat cham chowder. Why?
Most of the planes can fly during windy times. But their speed decreases. Only small aircrafts like Cessna are affected by these wings. So they cannot fly.
Airplanes all have different speeds.
Speed, altitude, and cost.
Airflow ans lift over the airframe is affected by the airplane's speed.
The speed, and therefore also the wavelength (for sound of a given frequency), are affected by temperature.
about 600mph at about 70,000 feet and 1,200mph at higher heights.