Wind
When the air seems calm, and you can’t feel a wind, it doesn’t mean that the wind has stopped blowing everywhere. There are always many winds keeping the air around the earth moving. In one place, there may be a soft breeze from the north. In another place, there may be strong gusts from the south.
Two different winds may blow near the same area at once. Near the ground, one wind may be pushing flags in one direction. But higher in the sky, another wind may be making the clouds scurry in another direction.
The fastest winds are high above the clouds, several kilometres up into the sky. These winds are called jet streams. Often, jet streams are connected. They form one huge, rushing river of wind that circles the earth, sometimes at speeds of more than 320 kilometres an hour. When an aeroplane takes off for a long trip, the pilot may fly into the jet stream because it can give the plane a powerful push.
Picture Credit : Google