Ask the pilot: How high do planes fly?
How high do planes fly?
The Boeing 737, the aircraft that I fly, has a maximum altitude of 41,000 feet (12,500m). This altitude has been determined by Boeing based on the characteristics of the aircraft and engines as well as on the capacity of the pressure cabin to maintain sufficiently high pressure. Different airplanes have different maximum altitudes, depending on their construction. For example, the Airbus A320 has a maximum altitude of 39,000 feet (11,900m) and the Boeing 747 45,000 feet (13,700m).
The air gets thinner higher up as the density decreases, so air resistance is lower at higher altitudes. This means that an aircraft can fly faster and use less fuel at increased altitudes. Consequently, we usually strive to fly as high as possible.
When an aircraft is heavily loaded, it is often not possible to reach the optimal flight altitude at the beginning of the flight. This happens especially on longer flights where the aircraft initially has many tons of fuel onboard that need to be lifted. During the flight, as the fuel is burned, the aircraft will be able to climb to a higher altitude.
Another advantage of flying high is that most weather phenomena, such as rain and thunderstorms, are in the troposphere (0–11,000m above ground) and flying above this reduces the risk of turbulence.
That said, winds can also have a significant impact on the choice of flight altitude. With a strong tailwind, for example, it can be better to fly at a lower flight altitude than would be optimal under zero-wind conditions.
Computer programs are used to find the optimal flight altitude for each flight.
Senior First Officer
Published: January 17, 2022