Big Bird?

Sam Worthington has made a career out of riding mythical flying animals.

Here's his debut, from Avatar, where he plays Jake Sully, tamer of the huge flying dragon-lizard-thing (thus making him savior of the "Navi"):

And here he is in Clash of the Titans, as Perseus, the first human to ride and tame a pegasus (thus maving him savior of the Argons):


Yeah, I should be writing that screenplay outline right about now...