US Airways has 7 DC-9's remaining, and it looks like the flight from PHL will indeed be the last, arriving at PIT about an hour after other 9's from ROC, ERI, and CRW touch down at PIT for the last time.
The DC-9 has served over 35 years as a workhorse for Allegheny/US Air/US Airways, and this is definitely a very significant retirement. The 7 remaining DC-9's are from a group purchased by US Air new in 1980 and were among the last new 9's to come off the production line. My guess is that N928VJ will be used for the very last flight, it's the only 9 that has the new tail colors on the basic bare metal scheme. Truly a great airplane, it will definitely be missed.