This type of breathing is not considered abnormal at high altitudes. However, if it occurs first during an illness (other than altitude illnesses) or after an injury (particularly a head injury) it ...

In the years since then, balloon flight technology has evolved from cloth balloons and open baskets to polyethylene balloons and metal pressurized gondolas that allow for high-altitude atmospheric ...

But what is cruising altitude and how do pilots ... most transport category aircraft can fly at high altitudes, but their performance varies on the type of aircraft and the manufacturer.