All express flights were branded as US Airways Express, and aircraft were no longer confined to operations out of their pre-merger hubs (America West aircraft could fly from Philadelphia to destinations other than Phoenix and Las Vegas, for example). The two airlines' operating certificates were merged in September 2007. After initially using the "CACTUS" callsign for the west fleet and "USAIR" for the east fleet, all aircraft began flying under a single "CACTUS" callsign and ICAO code "AWE" in September 2008. Former America West aircraft were distinguished apart from US Airways pre-merger aircraft by their use of registrations ending in "-AW", while pre-merger US Airways aircraft used registrations ending in "-US". US Airways would later merge with American Airlines in 2013.