FWIW, you should check out the Hawaii forum linked below.
That said, US Airways doesn't fly to Hawaii, so I assume you mean United. As been mentioned, you might have some problems returning but getting here shouldn't be a problem. Just make sure you aren't traveling on high-frequency days (weekends, days after Thanksgiving, etc) and check the loads using the Availability Tool or
CT ITN. I know a few UA employees who fly standby out of HNL and they've reported the same as above.