Meteorologists use the location of some of the jet streams as an aid in weather forecasting. The main commercial relevance of the jet streams is in air travel, as flight time can be dramatically affected by either flying with the flow or against the flow of a jet stream.n each hemisphere, both upper-level jet streams form near breaks in the tropopause, which is at a higher altitude near the equator than it is over the poles, with large changes in its height occurring near the location of the jet stream.