The Sky Train service to the 44th St. station provides people who want to rent a car with an option to save 40-50% on the cost of the rental. This is because the main car rental at the airport (which isn't really at the airport) charges ridiculous fees and taxes.

Here's the alternative, the one I booked for my husband. Book your car with Enterprise at the "Phoenix East" location. Call the Enterprise office directly when you're ready to get on the train, they will come to the Sky Train station to pick you up. Ask for directions, they told me "Exit the station down the escalator to the right and look for the shuttles pickup area." They also said taking the Sky Train would save a $20 taxi ride from the airport, perhaps they meant RT (not sure).

Same procedure in reverse to return to the airport AND there is a baggage check at the 44th St. station for outbound pax on Southwest or USAir. The quote for a 2-day economy car rental at the airport was $135 and $79 from the Phoenix East location. A no-brainer.

I lived in Phoenix for over 20 years and have been preaching against renting a car at the airport for a LONG time. Enterprise via the Sky Train is the ticket. I have no affiliation at all with Enterprise, I just like to spend money wisely.