Rishi Kasyapa had two wives; Kadru and Vinata (daughter of Daksha). The first wife became the mother of a thousand snakes (Nagas), while the second wife, Vinata gave birth to two eggs, one of which was very late in opening. Therefore, she hastily broke the egg-shell because of which a handicapped child (without legs) was born. The loving parents named the child Aruna. The second egg opened naturally and Garuda, the bird with large wings, was born.
Aruna, even though disabled, rose to an exalted position as the charioteer of the Sun-god, Surya. Since ancient times, he continues to spread Sun's energy daily around the world, sustaining us with vital nourishment without which life would be impossible. (His brother Garuda, also known as Vainateya, became the Vahana (vehicle) for Lord Vishnu).
Early in the morning every day, all living beings look eagerly to the eastern sky awaiting the arrival of Aruna; he does not fail them even a single day. He is ever punctual and appears with his master, Lord Sun, brilliantly painting the sky red (Aruna also means red). Riding majestically across the sky, he guides the seven horses in their majestic travel towards the Western horizon. No wonder that the ancients gratefully named sun-rise after him as Arunodaya, the appearance of Aruna!
Lovingly, his master Surya, the Sun-God, identified himself closely with his devoted charioteer and wanted himself also to be known as Aruna!
See also: http://www.apamnapat.com/articles/StoriesFromMahabharata400.html about Garuda.
School for children with