Though the coach has an enclosed interior, passengers usually sit topside on benches, the better to take in the passing show: the wind and sun, fresh air, wildflowers, townspeople waving and, of course, the occasional whiff of horse emissions.
Look, from a pure PR perspective, you could break out everything into its 25 component parts, spent several weeks selling the component parts of wind energy, and passing it -- would it have made a PR difference?