Perspiration is a normal physiologic response to the environment on an airplane.

Some factors, such as temperature and humidity, are obvious.

There is one that is apparently less so. Airplane cabins are simply not the environment most of our bodies are used to, no matter how frequently we fly. At cruising altitudes, cabins are pressurised at pressures equivalent to about 1800-2400 m (6000-8000 ft) above sea level.

Most of our bodies are not used to that. Our bodies therefore go into a mild state of hypoxia (lower oxygen concentration in the blood). This in turn will activate our sympathetic nervous system – that is, the fight-or-flight (haha) response. For more details see Physiological Adaptation of the Cardiovascular System to High Altitude.

A consequence of increased sympathetic activation is the secretion of sweat from our sweat glands.

Your sympathetic nervous system may be further activated by stress, anxiety, or a number of other factors.

So there's really nothing you can do to prevent your body from perspiring when you travel on a plane. Just let your body go about its usual sweaty business, and prepare for the repercussions.

Perspiration is a normal physiologic response to the environment on an airplane.

Some factors, such as temperature and humidity, are obvious.

There is one that is apparently less so. Airplane cabins are simply not the environment most of our bodies are used to, no matter how frequently we fly. At cruising altitudes, cabins are pressurised at pressures equivalent to about 1800-2400 m (6000-8000 ft) above sea level.

Most of our bodies are not used to that. In response to the low barometric pressure, our bodies go into a mild state of hypoxia (lower oxygen concentration in the blood). This in turn will activate our sympathetic nervous system – that is, the fight-or-flight (haha) response. For more details see The autonomic nervous system at high altitude and Physiological Adaptation of the Cardiovascular System to High Altitude.

A consequence of increased sympathetic activation is the secretion of sweat from our sweat glands.

Your sympathetic nervous system may be further activated by stress, anxiety, or a number of other factors.

So there's really nothing you can do to prevent your body from perspiring when you travel on a plane. Just let your body go about its usual sweaty business, and prepare for the repercussions.