the air is thinner
The density of air decreases at higher altitudes.
because there is low pressure at higher altitudes
Yes. Both to take off and to land. There are several major airports at high altitude (like Mexico City and Denver, CO) that are real problems for pilots.
Yes.
They have cooler temperatures than places at lower altitudes.
altitudes
No, though higher altitudes will be at the freezing point more often.
You get polycythemia
They have cooler temperatures than places at lower altitudes.
PAULY D IS A BEAST ik this is not the answer
Jet airplanes fly at high altitudes because it is more fuel efficient. Flying at higher altitudes uses less fuel than flying at lower altitudes.
Yes the sun is more direct at higher altitudes.