By Andrea Romano
October 29, 2019

Have you ever felt like your flight to an east coast city took way less time than a flight headed out west? You’re not alone.

In fact, if you were to look at a round trip itinerary between Los Angeles and New York, you’ll notice that there’s a big difference in flight time to each city. In fact, there's usually about an hour difference, depending on which direction you’re facing.

Many people swear that the earth’s rotation should make going west much faster since the earth spins toward the east (which is why the sun rises in the east and sets in the west). But truthfully, this so-called logic doesn’t really hold up when you’re up in the air, and your extra-long flight to the west coast is actually caused by several other factors.

How The Earth’s Rotation Works

There are a few basic things you need to know about the earth's rotation in order to understand its impact on air travel. Firstly, the planet is constantly rotating on its axis in an eastward (counter-clockwise) direction. This explains why the sun’s light moves from east to west. If you’re not convinced, grab a globe and a flashlight. Shine the light onto the globe while rotating it to the right. You’ll notice that the light seems to be moving in the opposite direction, even though the globe is the only thing moving. 

Cornutus/Getty Images

Here’s where a lot of people start getting confused. Because we know the earth is rotating eastward, there is an assumption that this motion would also help hurl westward flights faster towards their destination. There’s just one problem with that. Everything on earth, not just the ground, but also the water (and even the atmosphere), is rotating in the same direction, Forbes reported. Since planes in the sky are being pulled eastward with the earth, it takes more time to go west. Think of it kind of like walking against the wind.

The Jet Stream

The jet stream is the real reason your flight time varies depending on the direction of your destination. Jet streams are air currents that happen at very high altitudes, including those which planes frequently fly in.

There are major air pockets in the atmosphere (known as cells) that move all over the world, according to the Cornell University Astronomy Department, and they can affect how long you’ll be sitting in that basic economy seat.

According to Cornell, the main cells on earth are the Polar cells (located near the earth’s poles) and the Hadley cells (which form near the equator). The earth’s rotation is faster at the equator because it’s the widest point on the globe. And since it’s faster, these Hadley cells move around the earth, north to south, at a quicker pace than polar cells, thus creating wind tunnels, also known as jet streams. These jet streams tend to move in a wavy pattern from west to east, aided by the earth’s rotation. So, yes, the rotation of the earth is a factor in this scientific dilemma, but it is not the main reason why your flight time is different depending on the direction of your flight. 

If your plane is flying along a jet stream going east, it can really pick up some speed. In fact, in February 2019, a Virgin Atlantic flight managed to hit a record-breaking 801 miles per hour on a flight from Los Angeles to London thanks to a jet stream.

But these jet streams come with their own hazards too, causing unpredictable weather and turbulence, according to CN Traveler.

Travelers heading west will just have to bide their time for an extra hour or so on their flight. However, eastward flights have also been found to cause more severe jet lag, so travelers headed east should be ready for a longer recovery time, even if their flight gets in earlier than expected.