Mechanical or Aerospace Engineering for working with Automobiles?

Junior in high school right now, and I'm pretty set on my future major and career for the most part. I really like automobiles and would like to obtain either a mechanical or aerospace degree in order to work with them. But I don't know which degree would be better. I hear aerospace engineers can work in the automotive field by improving aerodynamics of cars. But mechanical engineers specialize in making engines, which is also really cool. They both seem kind of similar...I can't really pick.