They are trying to make their training more efficient. Closing Phoenix means they will use those resources/budget towards the other training centers. Why more US airlines don't centralize their training is beyond me. Either way, unless the pilot training lives around DFW training center for example, the rest will have to travel anyway. I'd make one mega training center for all fleets and pilot types and have the pilots travel to it. Would make the HR/Admin, training way more efficient.