Interestingly, how high planes can fly and how high they do fly are not the same measurement.
Most planes have a maximum operating altitude – the highest they can fly safely – but they rarely, if ever, operate at that height.
More often, aircraft fly at a standard cruising altitude determined by their engines, weight, fuel efficiency, cabin pressurization systems, and external factors such as weather and air traffic control protocols.
For most commercial airliners, the standard cruising altitude is between 33,000 and 42,000 feet (10,058 to 12,801 m), depending on the aircraft type. The common cruising altitude for small airplanes and helicopters is around 10,000 feet (3,048 m).
This article discusses how high commercial and small airplanes fly and the factors influencing common cruising altitude.
How High Do Commercial Planes Fly?
How high a commercial plane can fly depends on the mechanics of the aircraft itself, the outside climate, and the altitude assigned by air traffic control (ATC).
Before taking off, airlines submit flight plans to air traffic control, which determines the best cruising altitude for the route.
Decisions are based on the performance and fuel efficiency of the aircraft as well as the other traffic in the skies.
Typically the cruising altitude for commercial jets is between 36,000 and 40,000 feet (10,972 to 12,192 m).
However, if ATC permits, passenger planes may fly higher or lower than this range, even up to 42,000 feet (12,801 m).
Aircraft also have a maximum operating altitude, also known as the certified service ceiling, which is defined by the FAA and refers to how fast a plane can climb.
When flying outside the service ceiling, planes may experience performance or efficiency issues, which is why it’s not common for pilots to do so.
Absolute ceiling refers to the altitude at which a plane can no longer climb – it can only maintain level height – and while it might be possible to reach, flying at this altitude is rare and impractical.
Additionally, since thousands of planes are in the air at any given moment, they all cruise at different levels.
For example, airplanes flying in different directions on the same route never fly at the same height and are at least a thousand feet from each other.
Aircraft flying eastward always stay at odd altitudes, such as 37,000 feet (11,277 m), while flights headed west occupy even altitudes, such as 36,000 feet (10,972 m).
How High Do Small Airplanes Fly?
Because small planes have different engines and aren’t pressurized like commercial aircraft, they must fly much lower.
The average altitude of small aircraft ranges from 2,000 to 10,000 feet (610 to 3,048 m).
All plane engines need oxygen for the fuel combustion that keeps them powered.
Commercial jets have bigger, more advanced engines and can maintain power at higher altitudes where the air is thinner.
In contrast, small planes typically have piston engines, which cannot operate effectively in the lower oxygen environment above 15,000 feet.
Additionally, small aircraft often aren’t pressurized like passenger planes and must remain at lower altitudes for the safety of the people onboard.
Pressurization is also one of the main reasons all aircraft have ceilings – if oxygen levels within the plane decrease, the pilot must be able to descend to a safer altitude quickly and efficiently.
How High Do Helicopters Fly?
Most commercial helicopters have a service ceiling between 10,000 and 25,000 ft (3,048-7,620 m); however, most operate at a cruising altitude of 10,000 to 15,000 ft (3,048 to 4,572 m).
The cruising altitude of helicopters depends on their mechanics – they rely on their propellers to maintain lift, so they must stay where the air can provide enough resistance.
Additionally, helicopters have different service ceilings for hovering vs. flying.
A hovering helicopter can only maintain lift much lower to the ground than one in motion.
Factors That Influence Cruising Altitude
While aviation technology has advanced and bad weather doesn’t usually endanger aircraft, avoiding storms wherever possible is still best practice.
The most effective way to get around bad weather is to get above it, so airplanes fly in the troposphere above 36,000 feet (10,972 m).
The troposphere is the part of Earth’s atmosphere where there are fewer clouds and weather changes aren’t as common.
If the weather does turn ugly, pilots report to air traffic control for further guidance, which may include changes in altitude.
The primary reason passenger jets fly at high altitudes is that air density is low in the troposphere.
Thin air creates less resistance, allowing plane engines to maintain power and speed while consuming less fuel.
Commercial airplanes require more thrust – and more fuel – during take-off, which is why pilots get to cruising altitude as soon as possible.
Even if the flight is short, it’s still more efficient for an aircraft to cruise for five minutes before beginning its descent.
Cruising altitude is also the height at which an aircraft can balance speed, fuel efficiency, and safety.
If a plane hits its maximum or absolute ceiling, there is much less oxygen in the air, so the engines must burn more fuel quickly to maintain level height.
The chances of striking a bird are higher at lower altitudes since birds typically fly within a set distance from the ground.
Bird strikes can cause costly damage to the aircraft, especially to the engines, and pose a risk to the passengers onboard.
It’s much safer for the aircraft (and the birds!) when a pilot reaches cruising altitude as soon as possible.
There are situations where the pilot may have to land the plane quickly and unexpectedly.
Such emergencies could include system malfunctions or health issues.
It can be challenging to land abruptly when these scenarios arise, so cruising altitudes are assigned with safety protocols in mind.
Most commercial aircraft fly at a standard cruising altitude between 33,000 and 42,000 feet (10,058 to 12,801 m), depending on the type of plane.
For small airplanes and helicopters, the common cruising altitude is around 10,000 feet (3,048 m).
Standard cruising altitude is determined by the plane’s engines, weight, fuel efficiency, cabin pressurization systems, and external factors such as weather, safety, and air traffic control guidelines.