It’s one of the weirdest things about air travel: You feel like the plane is moving very fast as it rolls down the runway, but once it’s in the air and reaches cruising altitude, you feel like you’re barely moving. When you look up at a passing airplane from the ground, it appears to be drifting leisurely rather than it actually moving at hundreds of miles per hour. Forget peanuts on the plane; Jerry Seinfeld should be asking what this cognitive gap is about. Let’s know this science about planes.
It turns out that planes and their seemingly slow appearance are relative. For spectators on the ground looking up at an aircraft, there are often no reference points to judge the aircraft’s movement; for example, clouds to pass through or any contrails (vapor trails) to measure. Instead, an airplane in the sky looks like a small point of light against a pure blue background thousands of feet away from you. Without a reference point, it is difficult to judge how fast an object is moving.
Another factor? The time it takes for the plane to cross our field of view. Because it’s so distant and tiny, a plane can stay in your field of view for a while – creating the illusion that it’s crawling (although, our brains know better). If it were flying closer to us, it would cross our field of view faster, giving us a better idea of its true speed. This effect is called motion parallax.
In a plane, there are few reference points
According to Flying Magazine, the average commercial aircraft cruises between 550 and 600 miles per hour. When you’re in an airplane (which is almost always painted white), you’re also moving at this speed. Because you are on a plane, following it rapidly, you cannot perceive how fast you are going.
Why being on an airplane feels so much slower than being in a car or train is, like the perception of an airplane’s speed at a distance, a matter of reference points (or rather, the lack thereof). In a car, you typically pass a variety of reference points that pass faster or slower along your field of vision, depending on how fast you’re driving. However, in a plane, these reference points are much fewer.
Sara Nelson, director of the NASA Iowa Space Grant Consortium at Iowa State University, analyzed the concept in an article published on The Conversation website, noting, “This is why you are so It’s hard to tell why you’re driving so fast on the highway and there’s just open fields and no trees around you.” Nielsen further said that if you were inside an airplane and looked out of the plane’s round window, you could see the plane on the ground. shadow, you can feel the true speed of the aircraft.
However, flights are indeed getting slower and slower
As aerospace educator Sara Nelson explains, the lack of a reference point is the main reason aircraft appear to move so slowly in the sky, when in fact they are traveling at about 575 miles per hour. But speaking of slow planes, the fact is that flying itself is slower today than it was 50 years ago. Reasons include airlines factoring potential flight delays into flight time and pilots flying at slower speeds to save fuel.
This fuel-saving practice seems to date back about 15 years. As a United spokesperson shared in 2008, “What we’re doing is flying at a more consistent speed to save fuel” (via NBC News). According to Forbes, JetBlue and Ryanair (since 2008) have also instructed pilots to slow down their flights as a result.
There are also practical and safety reasons why today’s planes are slightly slower than they used to be. According to Wendover Productions, the turbofan engines used in most commercial aircraft are most efficient between 400 and 600 miles per hour. Faster speeds require jet engines, which consume fuel at breakneck speeds, and faster speeds—for example, around the sound barrier, which jet engines can break—become increasingly dangerous. So, with all of that in mind, maybe it’s not such a bad thing for planes to slow down closer to what we perceive.
