How come? ?The pressure, temperature and oxygen levels in the cabin fluctuate, and the humidity level is lower than it is at sea level,? says family medicine physician Matthew Goldman, MD.

Feeling short of breath on a plane is a common physiological reaction to the lower air pressure and decreased oxygen levels in the cabin. Although modern aircraft are "pressurized," they are typically pressurized to an equivalent altitude of 6,000 to 8,000 feet, rather than sea level. At these altitudes, the air is thinner, meaning your body takes in slightly less oxygen with every breath than it does on the ground. Additionally, the extremely low humidity in airplane cabins (often below 10%) can dry out the mucous membranes in your nose and throat, potentially causing a sensation of tightness or "bronchospasm," especially for those with mild asthma. In 2026, travel doctors recommend staying well-hydrated and moving around the cabin to keep blood flowing, as the combination of lower oxygen and sitting for long periods can exacerbate feelings of lethargy and respiratory discomfort for many passengers.