I guess I must have been really unlucky with America West in that my experiences differ.
I lived in Phoenix for 9 years. Most of the time, I flew Southwest but occasionally I had to take an America West flight because of schedule or destination. I would say that in the 9 years I lived there, I was on America West about 8 times. Every time I flew them they were anywhere from 45 minutes to 3 hours late. I can't tell you all the reasons for the delays but I do know that only a few were in any way weather related. I tried to avoid America West whenever I could.
With my luck, if people had known I was going to be on the plane, they probably would have avoided that flight too!