From Hindupedia, the Hindu Encyclopedia

Vayu means air.

Vayu is also a Vedic deity, and name of the presiding deity of air. Vayu is represented as a minor God-army called Maruts, who form seven sets of seven each. There are forty nine Maruts in all. They are the younger brothers of Indra.

Vayu represents strength and tamo guna, and is a close associate of Vedic Rudra. He is also a devotee of Vishnu.

The great characters Hanuman of Ramayana and Bhimasena of Mahabharata are said to be born by Vayu's grace, and are referred to as the sons of Vayu.

Vayu in the context of life-breath is referred to as prana. There are five pranas that conduct the human system - prana, apana, vyana, udana and samana.