Seems everyone (or most) who repeat trips to Zihua/Ixtapa, and those first timers, continue to struggle with airline connections. May I suggest that all of you do as I have and contact Southwest Airlines asking them to consider servicing Zihua/Ixtapa. With their purchased of AirTran, they now have the access (and required authorization) to the flights that AirTran had to the Caribbean side of Mexico, so flights to the other coast shouldn't be that big of deal. I'd love to have a direct flight from Milwaukee but would gladly settle for a reasonably priced same day flight through one of there hubs. With their hubs in the Phoenix and Dallas, seems like a great place to continue on to Zihua.
I would encourage you to go to www.southwestairlines.com and go to the bottom of the page, click on "contact us" and let them know that you would like them to consider adding service to Ixtapa/Zihuatanejo. It can't hurt.