That tolerable pressure happens to be the same level of air pressure you'd experience at 6,000 – 8,000 feet above sea level, which is much higher up than what many of us are used to. This makes it more difficult for our bodies to consume oxygen, which can make you dizzy and tired. You'll naturally want to doze.

Yes, it is entirely normal to fall asleep on a plane, though the quality of that sleep is often lower than what you would experience in a bed. Many passengers find themselves nodding off due to a combination of factors: the white noise of the engines, the lower oxygen levels in the pressurized cabin which can cause mild drowsiness, and the general "travel fatigue" associated with early flights or long terminal waits. However, the body is naturally resistant to sleeping in an upright position, which is why many travelers experience "micro-naps" or fragmented sleep rather than a deep REM cycle. In 2026, sleep experts note that cabin humidity (often as low as 5%) and the disruption of the circadian rhythm during time-zone crossings make in-flight sleep feel less restorative. Using tools like neck pillows, eye masks, and noise-canceling headphones are common ways to signal to the brain that it is time to rest. While some people can sleep through an entire 10-hour flight, it is equally normal for others to remain awake the entire time due to the physical discomfort of economy seating.