Jet Streams According with the reading, jet stream liken to a "River of air". They take place in high altitudes approximately 20,000 feet. In addition, their average speed is around 190 miles per hour. There are two main jet streams between the North Pole and the equator, the first one is known as subtropical jet; it occurs from southern to border of continental Unites States. The second is the polar jet which develops in Idaho and Montana. Both streams cause storms and awkwardness to air lines. This situation might be illustrated if we imagine a trip from Los Angeles to New York. The travel will last as much as a hour less at the return because of the strong tailwind. However, the airplane will spend more fuel since; it has to overcome the head wind. Furthermore, there will be more turbulence because; weather conditions will be affecting by the position of the jet stream