I hope someone can help me figure out what movie I am remembering. I saw it when I was young, it was probably made in the 80's sometime. It involved a horse (unicorn?) who could fly if he ran very very fast (I think when he ran he grew wings), and a witch who was turning children into bricks to build her castle. It's not Unico, but nobody I have ever asked has heard of it. Please tell me I'm not crazy, or remembering a very vivid (very bizarre) dream. Thanks in advance!

Quinn F