If you’ve ever had a roundtrip and flown east to west and back again, or vice versa, you may have noticed that there is a difference in flights times between the two.
Flying east is faster than flying west due to one reason: jet streams.
Why It’s Faster to Fly East Than West
Simply put, jet streams are a series of fast-flowing narrow air present in high altitudes – and is the reason why flying east is faster than flying west.
These jet streams have a strong effect on planes, as planes flying east can pick up additional tailwinds, speeding up their journey and reaching their destination more quickly.
In contrast, a westward flight would mean a plane that would be flying against this powerful wind.
The most important jet streams are the Polar and Sub-tropical streams; which are located at 60° and 30° north and south of the equator.
The Polar stream is the stronger of the two, and it causes much faster winds than the Sub-tropical stream. Most planes flying transatlantic or transpacific routes use the Polar stream.
Related: Why Are Westward Flights Slower Than Eastward Fights?
Flight Speed When Flying East vs. West
In 1952, on a flight that took off from Tokyo, Japan, and landed in Honolulu, Hawaii, jet streams reduced the flight time from 18 hours to only 11.5 hours.
This is the first known use of taking advantage of jet streams in commercial aviation.
Today, if you fly from New York to London, the flight takes six and a half hours, but when flying from London back to New York, it takes seven and a half hours due to the influence of jet streams.
Jet streams even affect short flights, such as when flying from Los Angeles to New York, which cuts the flight time by an hour than if the destinations were reversed.
The Earth’s Rotation Doesn’t Affect Flight Times
Contrary to popular belief, the Earth’s rotation actually has no effect on flight times, despite the Earth rotating from west to east.
While the speed of the Earth’s rotation at the equator is approximately 1,000 km/h, and would imply that westward flights should take more time, an aircraft actually moves away from its destination as it continues to spin with the earth because the earth’s atmosphere rotates in addition to its surface.
There is More Turbulence When Flying West
Due to the jet steams when flying from east to west, there is actually more turbulence on westward bound flights.
The jet streams blow against a plane and results in strong headwinds.
Even though turbulence isn’t dangerous, pilots will anticipate any turbulence before takeoff by receiving a weather briefing, and once airborne, pilots listen for reports of turbulence from other flights.
Pilots will often aim to avoid turbulence by adjusting the route of the flight or adjusting altitude.
Fly West If You Want to Minimize Jet Lag
Flying east may result in shorter flight times, but it will also result in more jet lag.
This is because you will cover several time zones and advance rather than delay the body’s internal clock, which is more difficult for humans to adjust to, and can result in more jet lag.
In short, due to most people’s endogenous circadian rhythm, lengthening a day is less troublesome than shortening it.
It’s Better to Fly West When Flying Around the World
If you want to fly around the world, it would be better to fly westward for comfort and eastward for economy and speed.
When flying westward, flight times are longer but more of your flight will be spent in daylight hours, so you can expect less jet lag and reduced discomfort overall.
