After America West management took over US Airways they stopped operating the Shuttle as an airline-within-an-airline. They stopped operating an all-coach subfleet of aircraft with its own livery. And when US Airways management took over American, the shuttle became an American Airlines product.
American is replacing the ‘Shuttle’ product in a couple of ways. They’ll no longer fly New York LaGuardia – Boston, and they’re introducing a new fare that’s meant to be ‘Shuttle-like.’