If you’re wondering how high planes fly, the answer is that it varies depending on the type of plane (private, commercial, military), its variant, as well as whether the flight is short-haul or long-haul.
Most commercial planes fly at altitudes between 30,000-42,000 feet, but private and military jets fly higher. The advantages of flying at higher altitudes include faster travel, better fuel efficiency, avoiding uncomfortable weather events, obstacle avoidance, and increased reaction time in case of emergencies.
How High Do Planes Fly? – By Airliner
The altitude at which a plane flies depends on many factors, including its size, function, and design.
Let’s take a look at the maximum and average altitude of the most popular airliners: the Boeing 737, Boeing 747-8, and Airbus A380.
Boeing 737 Altitude
- Feet: 37,000 – 41,000 feet
- Miles: 7.0 – 7.7 miles
- Kilometers: 11 – 12.5 km
- Meters: 11,000 – 12,500 meters
- On Average: 31,000 – 34, 000 feet
Boeing 747-8 Altitude
- Feet: 43,000 feet
- Miles: 8.1 miles
- Kilometers: 13.1 km
- Meters: 13,100 meters
- On Average: 35, 000 feet
- Feet: 42,000 feet
- Miles: 7.9 miles
- Kilometers: 12.8 km
- Meters: 12,800 meters
- On Average: 36, 000 feet
Why Do Planes Fly So High?
Planes fly at high altitudes for decreased air resistance, improved fuel efficiency, better avoidance of weather, obstacles, and better safety.
The air is thinner at higher altitudes, resulting in lower air resistance, which allows the plane to fly faster. Flying too high can be dangerous, though, so all planes have a maximum safe altitude a pilot should not exceed.
Since there’s lower air resistance at higher altitudes, a plane can cruise without burning fuel on overcoming resistance. Lower fuel usage allows airlines to decrease fuel costs. An altitude between 32,000 – 38,000 feet is ideal for most planes to maximize fuel efficiency.
Flying above weather events
By flying at high altitudes, commercial planes avoid weather events like thunderstorms or rain, which could potentially damage the aircraft. While planes can usually fly through rain and thunderstorms safely, doing so can result in dangerous turbulence, so it’s better to avoid doing so.
The higher a plane flies, the less likely it is to encounter land-based obstacles like skyscrapers or mountains. Flying higher also helps reduce noise pollution from the plane for people on the ground. At an altitude of 35,000 feet, there are no birds or insects in the sky either, which further eliminates the chances of bird collision.
In an emergency situation, flying at a higher altitude gives the pilots more time to react, since it’d take longer for the plane to reach the ground. These extra minutes during an emergency could be vital in preventing a plane crash and saving the lives of everyone onboard.
Short-Haul Flights vs. Long-Haul Flights
Short-haul flights are those that generally last between 30 minutes to 3 hours, and long-haul flights last over 9 hours. Planes on short-haul flights cruise at lower altitudes, 29,000-33,000 feet, while planes when flying long-haul cruise between 33,000-38,000 feet.
This difference in cruising altitudes is because planes consume fuel when rising to higher altitudes, so it’s more economical for shorter flights to save the time and fuel spent ascending and descending.
Another benefit of different altitudes is that it creates separate flight zones for short and long flights, which makes it easier for air traffic control to give aircraft directions. Short flights also usually involve two-engine planes, while long-flights will involve 3 or 4 engine planes. The former cost more fuel to ascend and descend, further incentivizing airlines to set short flights on lower altitudes.
What Happens If a Plane Flies Too High?
The maximum height that most commercial airlines fly is 42,000 feet, which is considered the maximum safe altitude for most planes. If a plane flies higher than 42,000 feet, or whatever other maximum altitude it was designed for, it will have difficulty generating enough lift to remain stable.
The decreased oxygen over 42,000 feet is also insufficient to fuel most plane’s engines, which can result in engine failure. In the event of engine failure, there is a higher chance a plane could crash. This is exactly what happened to Pinnacles Airlines flight 3701 in 2004. The plane flew to 41,000 feet, experienced engine failure and crashed, with both crew members abroad dying.
Why Aren’t Small Planes and Helicopters Able to Fly As High As Planes?
Small planes typically use turboprop or piston engines, which are not powerful enough to lift a plane to higher altitudes. Most small planes can’t fly at higher than 15,000 feet for this reason. A more powerful engine is needed to climb higher than 15,000 feet.
Helicopters fly under 10,000 feet usually since they’re designed for flying short distances, and most helicopters perform roles like military combat, troop transport, medical evacuation, law enforcement, that don’t require reaching higher altitudes.
There are also health risks like hypoxia to consider when flying helicopters and small planes at higher altitudes.
Private Planes vs. Commercial Planes vs. Military Jets Altitude
Private jets generally fly at higher altitudes than commercial aircraft. The average private jet will cruise at around 41,000 feet, and the maximum altitude of most private jets is 45,000 feet; this is noticeably higher than most commercial planes’ maximum altitude of 42,000 feet.
Private jets fly at higher altitudes to avoid air traffic, and private planes are usually designed to ascend and descend faster than commercial planes.
Related: How High Do Private Jets Fly?
The average commercial jet will cruise at around 35,000 feet. These aircraft are designed to maximize fuel savings for airlines and provide the most comfort for passengers. The engines of these planes are fuel optimized, so they have lower climb rates than private jets.
US military aircraft can exceed altitudes of 50,000 feet. The maximum possible altitude for a military aircraft is not publically disclosed due to security concerns. Different military jets are designed to fly at different altitudes.
Most fighter jets fly at an altitude between 45,000-51,000 feet, but some like the F-22 Raptor can fly as high as 65,000 feet by being able to ascend vertically.
In conclusion, most commercial planes fly at altitudes between 30,000-42,000 feet, but private jets and military aircraft can fly higher. Most commercial planes fly at high altitudes for faster travel, better fuel efficiency, avoiding uncomfortable weather events, obstacle avoidance, and increased reaction time in case of emergencies.