Why the Jet Stream Is Helping Some International Flights Arrive Early

03.11.2023 - 00:57 / nytimes.com

Passengers who were on British Airways’ Flight 112, from Kennedy International Airport in New York to Heathrow Airport outside London, received some good news early Thursday morning. The flight, which normally would have taken about six hours, was going to arrive 50 minutes early.

Other flights traveling east over the Atlantic Ocean this week have been arriving ahead of schedule, up to an hour early in some cases, thanks to a jet stream that has been blowing in their favor.

A United flight that departed from Newark Liberty International Airport on Tuesday night, for instance, arrived 58 minutes early at Charles de Gaulle Airport near Paris, a flight that normally takes about seven hours, according to FlightAware, a site that tracks aviation traffic.

An Emirates flight on Tuesday from Dallas Fort Worth International Airport to Dubai in the United Arab Emirates was supposed to take 13 hours 44 minutes. It landed 57 minutes early, according to FlightAware.

Here’s what you need to know about these early arrivals.

A jet stream is a band of strong winds blowing from west to east in the upper levels of the atmosphere, or about 30,000 feet from the ground, according to the National Oceanic and Atmospheric Administration.

One way to understand how a jet stream could affect flights is to think about a boat on water, according to Jennifer Stroozas, a meteorologist with the Aviation Weather Center at the National Weather Service.

“The atmosphere behaves a lot like a fluid,” she said. “If the water is calm, a boat will also remain still. If the water has a strong current, it will naturally push a boat along.”

When planes fly within a jet stream, strong winds can push the plane along faster, Ms. Stroozas said.

Commercial flights typically fly at a speed equivalent to a ground speed of about 570 miles per hour, according to Richard Levy, an aviation consultant who used to fly commercial aircraft.

The jet stream over the Atlantic this week has been helping flights go faster than their average speeds. The British Airways flight from New York to London, for example, reached a flying speed of 734 m.p.h.

Kevin Kuhlmann, a professor of aviation and aerospace science at the Metropolitan State University of Denver, said that it was common for jet streams to speed up flights traveling from west to east.

In the summer, it’s more common for flights to be affected by a jet stream when they are farther north. In the winter, the jet stream can shift south, Mr. Kuhlmann said.

That shift “could create a situation where it’s given a boost to that traffic,” he said.

Jet-stream-aided flights aren’t limited to those that cross the Atlantic. Mr. Levy said he was used to jet streams speeding things up when he was flying east over the