What was the story?

Many Years ago, at school, we were tolld the story of a man who was trying to escape from a deep place (could have been the underworld, but I don't remember, it was about 55 years ago).

He escaped by sitting on the back of a flying bird, but the bird needed to be fed, and before the journey was over he ran out of meat to give the bird.

In order to complete the journey, he cut pieces of his own flesh to feed the bird.

 I have never been able to trace this story, and my son, who has an interest in Mythology, thinks I've dreamed it. Can anyone help?