Lightning, The White Stallion
An expensive horse is stolen from a man. The robber is driving away with it and gets hurt because he is drunk. The horse escapes before a bus full of children being brought to school arrives. A girl offers to stay with the man in the hospital, and he tells her about the horse that escaped. She finds it, and offers to take care of it until he is let out of the hospital.
The movie was made when my parents were in high school so it doesn't have very good actors and it's very slow, which makes it difficult to enjoy the story.
Also, I noticed that they used at least two horses in the movie, and I know that because they looked very different. One was an Albino with pink around its eyes and nose and a long, white tail. The other was white with grey dapples and a shorter tail with black on it. LOL!