In time the rail may end up connecting to the airport. The important thing is the first stretch, and getting it approved in the first place.
This is just the beginning.
It may also shoot down Scottsdale road all the way to airpark, (Although I don't think I like the idea).
I would like it to connect to Sky Song though (connect three ASU branches). There was also talk of the rail shooting down the I-10 all the way to Westgate. -Mixed feelings on that one too.
Here's a thread on Light Rail if you want more info:
http://www.phxloftnetwork.com/forum/vie ... 28&start=0
I would think that in time the rail may get approved to connect with Sky Harbor. (Next 5 years or so)
I cannot remember why it isn't connected currently, Phoenix is known for having the major W Coast airport- but if memory serves me correctly, I think there was a good argument for why it isn't going in currently.