A narrow band of very strong westerly winds at high altitude in the mid-latitudes, which shortens or lengthens flights depending on whether they fly with it or against it.
What it is
Jet streams form along the boundary between air masses of very different temperatures, near the tropopause at roughly 9 to 12 kilometres up, precisely where airliners cruise. They generally blow from west to east, and their cores often exceed 100 knots; in winter they can top 200 knots (about 370 km/h).
That is why a flight from New York to London is usually about an hour shorter than the return. North Atlantic tracks are drawn up daily around the jet: eastbound flights ride it to save time and fuel, while westbound flights steer clear. In 2020 a British Airways Boeing 747 crossed from New York to London in under five hours on an exceptionally strong jet stream.
The edges of the jet can produce clear-air turbulence, which is invisible and does not show on the aircraft's weather radar. Aviation forecasts flag it so crews can pick smoother levels, but it cannot always be avoided, which is why passengers are advised to keep their seat belts fastened even when the sign is off.
Related terms
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This page was last updated on October 9, 2026
APA
Vuelopedia. (2026, October 9). Jet stream. Retrieved October 18, 2026, from https://vuelopedia.org/en/glossary/jet-stream
MLA
“Jet stream.” Vuelopedia, Fundación Poderia, 9 Oct. 2026, vuelopedia.org/en/glossary/jet-stream. Accessed 18 Oct. 2026.
Chicago
Vuelopedia. “Jet stream.” Fundación Poderia. Last modified October 9, 2026. https://vuelopedia.org/en/glossary/jet-stream.
Harvard
Vuelopedia (2026) Jet stream. Available at: https://vuelopedia.org/en/glossary/jet-stream (Accessed: 18 October 2026).
BibTeX
@misc{vuelopedia_en_glossary_jet_stream,
author = {{Vuelopedia}},
title = {{Jet stream}},
publisher = {Fundación Poderia},
year = {2026},
date = {2026-10-09},
url = {https://vuelopedia.org/en/glossary/jet-stream},
howpublished = {\url{https://vuelopedia.org/en/glossary/jet-stream}},
urldate = {2026-10-18},
note = {Accessed 2026-10-18}
}Wikipedia
{{cite web |url=https://vuelopedia.org/en/glossary/jet-stream |title=Jet stream |website=Vuelopedia |publisher=Fundación Poderia |date=2026-10-09 |access-date=2026-10-18 |language=en}}