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We’ve all looked up at the sky and seen airplanes flying high above our heads, looking like tiny specks in the sky. But how high do planes really fly?
Commercial planes typically fly at a cruising altitude between 30,000 and 43,000 feet (around 5 to 7 miles). These heights allow for optimal engine performance and efficiency while also avoiding most weather. Smaller private airplanes tend to max out at around 13,000 to 15,000 feet.
With all the different types of planes and aircraft in general, you could spend weeks reading about how high all the different types can fly. So for the sake of conciseness, we’re going to focus on what you’re really interested in – commercial airplanes. These are the planes that you’ve likely been in yourself, looking down at the world from high above, wondering just how high you really are.
All of the information in this article comes from countless hours of research and discussions to ensure that you’re getting the most accurate information possible. We’ve been in the aviation industry for years and have delved into just about every corner of all things flight, so rest assured knowing that you’re getting the best information out there.
How High Do Planes Fly?
If you’ve been on a plane and looked out the window or you’ve ever even just looked up at the sky and seen them flying overhead, you know one thing for sure – they fly high. If you’re looking down at the ground from a plane at cruising altitude, you can’t make out much of anything besides general shapes and colors. Everything down there just seems so tiny.
So how high do planes actually fly? Here’s a quick look at four of the most common commercial planes in production and their service ceilings (how high they can fly).
Commercial planes typically fly between 5 and 7 miles in the air at an altitude of somewhere between 30,000 and 43,000 feet. Of course, certain aircraft (such as military aircraft, for example) can fly much higher, but we’re going to go out on a limb and assume the vast majority of us will never go higher than a commercial airliner.
Just to get a sense of how high planes fly, think of Mount Everest, the tallest mountain in the world. The peak of Everest is a staggering 29,032 feet high. But even that is lower than the bottom of the altitude spectrum that planes fly at. So if you’re flying in a commercial plane, you’re up higher than anyone on any place on the Earth can ever be!
Why Do Planes Fly So High?
Now that you know how high planes fly, this then begs the question why do they fly so high? With how many years of research, engineering, and development that has gone into the air of flying over the past 100+ years, there’s got to be a reason for it, right? All the airlines didn’t just get together and decide to fly between 30,000 and 43,000 feet, did they?
There are actually a small handful of reasons why planes fly so high, but let’s focus on the biggest ones: airspeed, engine efficiency, and weather conditions.
Engine Efficiency and Airspeed
At the heights that planes fly at, the air is much thinner than it is down here at the ground level. That’s why the cabins of airplanes need to stay pressurized and why they always demonstrate the use of oxygen masks before the flight takes off. The air is so thin at cruising altitude that it’s hard to even get enough oxygen out of it to breathe like normal. But this thin air lets the airplane’s engines operate at near-optimal conditions.
This thinner air allows for the engines to produce less thrust than they do closer to the ground while simultaneously increasing airspeed due to the reduction in air resistance. So these high altitudes mean that the planes can fly faster while the engines are running far more efficiently and burning less fuel. It’s a win-win-win situation.
Avoid Weather Conditions
The other major reason that planes fly at such a high altitude is to be above most major weather conditions and situations. Once the aircraft gets above the clouds, they are out of the crosshairs of most of the adverse weather conditions that you don’t want to be flying through, such as lightning, rain, and strong wind.
Don’t let that idea scare you though, planes are built to withstand adverse weather conditions, and rain and lightning are almost never going to do anything that could actually put you or the flight at risk. But the wind, especially strong jet stream winds, can buffet the plane around and make for an uncomfortable ride that’s sure to turn a few stomachs. For this reason, the height of each flight will be decided on in real-time, depending on wind conditions and where the jet stream winds are located at that time.
What Happens If Planes Fly Higher Than They Should?
If everything is better at higher altitudes, why don’t planes fly even higher than 30,000 to 43,000 feet? Thin air is better for a plane’s engines, but only up to a certain point. At high enough altitudes (above the 43,000-foot ceiling), the air is so thin that the engines are not able to produce enough thrust. This loss in thrust leads to a loss in the ability of the wings to produce sufficient lift to keep the plane in the air. As you can imagine, this can lead to disaster.
This super-thin air can also have effects on the passengers and crew of the plane in the event of cabin depressurization. If the cabin loses pressure, there’s something known as time of useful consciousness that describes the amount of time a human can stay conscious in those conditions. There’s a standard protocol in commercial aircraft that will cause a rapid descent to a lower altitude in the event of the cabin losing pressure.
During the descent, the passengers and crew will typically have around 15-30 seconds of useful consciousness to get situated and put on their oxygen masks if it occurs at typical cruising altitude. But if the plane is flying too high – say around 50,000 feet – this time drops all the way down to around 5 seconds, which wouldn’t be enough time to put on the masks and remain conscious.
Why Helicopters And Small Planes Don’t Fly As High
You now know how high commercial airplanes fly and why they do it, so you might be wondering why other aircraft – such as helicopters and smaller planes – don’t fly that high. Wouldn’t it be better for them too?
In the case of helicopters, they typically stick to around 10,000 feet or lower, and that’s due to a couple of reasons. First and foremost, helicopters use rotating blades to generate the pressure differential that allows for lift instead of the airfoils (wings) on an airplane. This limits how high they can fly to begin with. They also are typically designed for much different (and usually shorter) flights than commercial planes, ones that don’t require such high altitude to reach their destination.
For smaller planes such as private planes, it’s mainly just a matter of the plane’s capabilities. These planes usually use a piston engine instead of the turbines found on commercial planes, which cannot produce enough thrust and lift to carry the helicopter up to heights of 30,000 feet and above. These planes also typically don’t have the cabin pressurization of commercial airlines so the pilot would not stay conscious at these heights.
Check out the table below to get an idea of how high some of the most common planes for new pilots fly at their service ceiling. As you’ll see the service ceilings for these smaller planes are typically less than half that of the big commercial airliners from above.
What’s The Altitude Record For A Plane?
As you can probably imagine, the altitude record for fixed-wing aircraft is not held by a commercial airliner as they weren’t designed for heights above those which you’ve read about already. But many people seem to think that the altitude record is held by the famous SR-71 Blackbird. However, that is actually not the case, even though it has been flown up to an astounding 85,069 feet back in 1976.
The altitude record for fixed-wing aircraft is actually held by Russian test pilot Aleksandr Fedotov. He reached a staggering height of 123,520 feet in his Mikoyan-Gurevich Ye-266 MiG-25 in 1977. Although some aircraft have been higher, that’s only for those launched from the air, not from the ground.
With everything you’ve read about commercial airliners in this article, just imagine the commotion that would happen if one of them tried to venture up to over 120,000 feet!