This has been happening since before the new year out of Philly. HP aircraft have been operating a morning ATL-PHL flight that turns to DEN, that's in addition to this month's schedule change which now has PHL-SAN, PHL-SFO, and the still flown PHL-PDX. It still seems though that US aircraft do quite a bit more flying out west in comparison, but that's showing the diversity in aircraft utilization from before the merger to now post merger. US would fly their aircraft to west coast destinations, and before hand, unfortunately aircraft would have to sit idle for longer periods of time before they could make timely departures to return to their east coast hubs. Now though, that times perfectly where the US aircraft arrive, let's say into PHX, and now they can still fly additional segments because HP always had the late banks out of PHX, 8PM/10PM to west coast cities and 9PM/10PM to east coast destinations. Since US metal just sat through this time, they now can fly late evening flights from PHX-SEA, PHX-SAN, PHX-ORD, PHX-DFW, PHX-MSP and then return back to PHX the next morning before their traditional US flight departure time, much better utilization as a whole.

I also just saw a PHX-CLT coming up that was noted HP metal so I am going to pick through the schedule and see what else they are beginning to fly on the east coast with HP metal.