If there was no wind a kite would only fly if the person holding the kite string started running, making their own wind as air started flowing around the kite. As the air flows over the surfaces of a kite the wind gets held back a little bit by the roughness of the fabric and the sticks. This friction is called drag. Any kite will always have some drag, and some kites are not able to fly without some extra drag being exerted on them. This additional drag is usually created by the tail of the kite, and allows us to make the kite point in the correct direction.
Air flowing through the tail pulls the bottom of the kite in the direction that the wind is blowing.
If more drag is caused by the tail than by the rest of the kite then the kite will always point into the wind. A single, long tail causes a certain amount of drag, but the same tail, cut into several lengths will produce much more drag, because the air is slowed down even more when it has to pass around several strips rather than just one. When the top of a kite turns to one side, the bottom of the kite pivots in the opposite direction. The drag caused by the tail tries to pull the bottom of the kite back to the centre again. The drag caused by the tail of a kite stops the kite from turning too much to one side or the other.