The actual plan is for Southwest to take over 4 gates in Terminal "E" from Delta. There was (is) only one terminal at PHL with 4 available gates (A-East) and that is due to BA, LH and others recently moving to A-West - where they should have been all along. US was instrumental in the design and significant funding support for A-West. They had nothing to do with the much earlier construction of A-East. I am personally appalled they would but DL into A-East myself - a carrier which barely serves the region, but what choice do they really have? The airport authority has been very cautious since just before the US-HP merger (and the DL hostile takeover attempt) and wants to avoid getting itself too imbedded into the single carrier hub situation without backup (WN). Essentially, the city doesn't want itself to be become another PIT with 37% of it's (PHL's) flights disappearing - even though there is a vast difference in the domestic and international O&D pool. Further, PHL was between a rock and a hard spot in that they enticed WN to start service in a major new airport (during the US BK process) and committed at that time to provide for additional growth beyond the original gate allocation. Also, US's highly publicized deteriorating service reputation, including baggage fiascos and labor problems, just doesn't exude a stable business model. I don't know if many are aware, but PHL is in the process of starting a $50M upgrade to A-East to make it more esthetically compatible with A-West. I am of the opinion that A-East should be principally International and even AA should be moved, except for their Caribbean services, elsewhere. I'd also speculate that PHL, or the city (as of now) hasn't taken Parker's 2008 (now 2007) PHL-China route as a serious endeavor, especially since there are no aircraft proposed to fly the route.