Sorry, I should have been more clear. I was checking on flightstats.com, not alaskaair.com. Flightstats.com is showing a 30 minutes delay as of last night, based on information filed with the FAA.

In any case, I did some additional research. One of USAirways largest Eastbound banks departs PHX between 2:50pm and 3:25pm. This would be the cause for outbound delays on AS 717, since it is scheduled for 3:17pm. Also, the corresponding inbound flight from SEA would be subject to all the US Airways traffic. So, it seems that AS needs to increase the block time on this flight by 30 minutes or, even better, re-schedule the flight 30 minutes later (iinbound and outbound).

Hopefully, AS's scheduling department will take a hard look at this flight. It could be a relatively easy problem to solve!