I've been on and off the site, can't remember where to post this. But, I've found a missing airport. Thanks in part to a recent trip to Phoenix, AZ.
The Airport is Phoenix-Mesa Gateway Airport. IATA: AZA, ICAO: KIWA, FAA LID: IWA.
Don't know how much help it is but here is the website and some info:
http://www.phxmesagateway.org/
http://en.wikipedia.org/wiki/Phoenix-Mesa_Gateway_Airport
Seems to be mainly served by the low cost guys ie Allegiant and Spirit.
Do I win a prize?