Anything in an airplane is automated: takeoff, flying and landing. Pilots make mistakes all the time, but they still need to do things manually to keep their practice high.
People just do not want to go in an airplane without any pilots. In metro's it's not that obvious if someone is driving it or not. But airplanes, 'we' want a human pilot to be in control, else we feel unsafe. I think the same can be said about cars.