An altitude expressed in hundreds of feet and referenced to the standard pressure of 1013.25 hPa, giving aircraft at height a shared vertical reference.
What it is
Above the transition altitude, pilots stop using the local airport pressure and set their altimeters to standard pressure: 1013.25 hectopascals (29.92 inches of mercury). Aircraft in the same area then measure height against the same datum, whatever the actual pressure, and vertical separation between them is preserved.
The level is given in hundreds of feet: FL350 means 35,000 feet on the standard setting, about 10,700 metres. The transition altitude varies by country: it is 18,000 feet in the United States, while in Europe it is usually much lower and set locally.
To keep traffic orderly, eastbound flights generally use odd levels and westbound flights even ones. Thanks to reduced vertical separation minima (RVSM), applied between FL290 and FL410 across much of the world, levels are stacked every 1,000 feet.
On Vuelopedia
The technical data on Vuelopedia model pages include the service ceiling, the highest altitude at which the type can operate.
Related terms
Cite
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This page was last updated on October 9, 2026
APA
Vuelopedia. (2026, October 9). Flight level. Retrieved October 18, 2026, from https://vuelopedia.org/en/glossary/flight-level
MLA
“Flight level.” Vuelopedia, Fundación Poderia, 9 Oct. 2026, vuelopedia.org/en/glossary/flight-level. Accessed 18 Oct. 2026.
Chicago
Vuelopedia. “Flight level.” Fundación Poderia. Last modified October 9, 2026. https://vuelopedia.org/en/glossary/flight-level.
Harvard
Vuelopedia (2026) Flight level. Available at: https://vuelopedia.org/en/glossary/flight-level (Accessed: 18 October 2026).
BibTeX
@misc{vuelopedia_en_glossary_flight_level,
author = {{Vuelopedia}},
title = {{Flight level}},
publisher = {Fundación Poderia},
year = {2026},
date = {2026-10-09},
url = {https://vuelopedia.org/en/glossary/flight-level},
howpublished = {\url{https://vuelopedia.org/en/glossary/flight-level}},
urldate = {2026-10-18},
note = {Accessed 2026-10-18}
}Wikipedia
{{cite web |url=https://vuelopedia.org/en/glossary/flight-level |title=Flight level |website=Vuelopedia |publisher=Fundación Poderia |date=2026-10-09 |access-date=2026-10-18 |language=en}}