In Dragonwings, to believe in Windrider's dream of flight is, to a certain degree, to believe in the supernatural. And if we put ourselves in the shoes of Uncle Bright Star in 1903, for example, we might understand how the idea of a human flying through the air really is seems like crazy talk. Windrider isn't sure whether his dream about meeting a dragon was real or not, but for us readers to care about his journey, we have to be open to the idea of such a thing happening. Moon Shadow is a great resource for this, what with all the lowdown on the Stove King, good dragons versus evil dragons, and which charms to keep with you to ward off evil.
Uncle Bright Star believes in the supernatural, but instead of believing in Windrider's dragon dream, he believes that supernatural powers can be found among communities of people.
Uncle Bright Star ridicules Windrider's dreams as selfish, but he suffers from a similar self-absorption in being too proud to be a good friend to Windrider.