the.com/jet stream

means A narrow band of fast-moving air high in the atmosphere that steers weather systems and gives planes a speed boost or headwind depending on which way they fly through it.

from The term emerged in the 20th century once high-altitude flight made the phenomenon obvious — pilots and meteorologists noticed powerful westerly currents miles up, and borrowed 'jet' (from the forceful, narrow gush of a fluid jet) to describe their fast, ribbon-like flow. The word 'jet' itself traces back through French 'jeter,' to throw, from Latin 'iactare' — so a jet stream is, at its root, a 'thrown' or forcefully propelled current, long before jet engines gave the word its modern aviation ring.