Jet stream defines an abnormal wind band that happens in high altitudes, nearly in the edge of troposphere. The wind should move strong to be technically called jet stream. Jet stream distinguishes North America into cold weather in the north and warm weather in the south area, therefore it is often called as polar jet stream.
Jet stream can influence the air travel schedule, although most of us do not aware of this issue. The lecturer explained the issue by giving out example of flight between New York and Los Angeles. When the flight goes according to the flow of jet stream, flight will be faster due to the jet stream force given to airplane’s tail. On the other hand, when flight goes against the flow of jet stream, the flight speed will be reduced and sometime turbulence on the body of airplane is occurred. This is the main reason why flight from Los Angeles to New York spends one hour longer than the return flight.