The kite in flight is generated when air flows around the kite's surface, producing low pressure above and high pressure below the wings. The interaction with the wind also generates horizontal drag along the direction of the wind. The resultant force vector from the lift and drag force components is opposed by the tension of one or more of the lines or tethers to which the kite is attached.The anchor point of the kite line may be static or moving.
The same principles of fluid flow apply in liquids and kites are also used under water.
Kites are very popular in India, with the states of Bihar, Jharkhand, Gujarat, West Bengal, Rajasthan and Punjab notable for their kite fighting festivals. Highly maneuverable single-string paper and bamboo kites are flown from the rooftops while using line friction in an attempt to cut each other's kite lines, either by letting the cutting line loose at high speed or by pulling the line in a fast and repeated manner. During the Indian spring festival of Makar Sankranti, near the middle of January, millions of people fly kites all over northern India. Kite flying in Hyderabad starts a month before this, but kite flying/fighting is an important part of other celebrations, including Republic Day, Independence Day, Raksha Bandhan, Viswakarma Puja day in late September and Janmashtami. An international kite festival is held every year before Uttarayan for three days in Vadodara, Surat and Ahmedabad.