[ardecila]

I'll say it again, there are good planning reasons to have metro or light-rail trains terminate at a transit center outside the airport with a people mover on the last mile. It's not just some bureaucratic kludge.

Transit centers can join many modes of transport at one place (bus, metro, light rail, commuter rail). They can be joined with a CONRAC so the rental car facilities are unified and accessible without a fleet of inefficient shuttle buses. The airport transit center can be "on the way" to other destinations in the city. The outlying transit center may be more convenient for workers who work in airport-related businesses, but not the airport itself. If the airport has multiple terminals, then there's no way a single train station can effectively serve all terminals without long walks anyway, no matter where it's located. Etc etc.