The pumped air is also used to create an air cushion around the pod to keep it suspended at high speeds. Also, solar panels line the top of the tube so that it is self powering.
It would not be built anywhere on the map in your link. The LA station is in Santa Clarita which is further north and west. It seems to me that he has laid out a route that avoids as much as possible dense urban areas. Even his extensions out to Vegas and San Diego by pass most of the urban development in the LA basin.
