This assumes envoy needs a replacement for the 145 though. Why doesn’t American serve the routes envoy does? Because mainline jets would prove to be not profitable so they have a regional that has smaller jets serve those route. American is simply moving around their assets so Piedmont takes the 145s and will likely gain routes the 145 serves while envoy gains more 170/175 and will lose markets and routes once served by the 145 but may gain more markets the 170 can serve. In my mind it makes the operations more efficient with each airline focusing and operating a single line of equipment.