All I can say is that for March 2008, the month before US filed to postpone the start of PVG service, China-U.S. traffic was up over 29% year over year. By July, the month before AA filed to postpone start of service, the YoY growth had dropped to 11.3%. While not specific to the China-U.S. market, overall Asia-U.S. traffic growth had dropped to about zero in June and turned negative in July.
Of course, all that has nothing to do with US' stated reason for postponing the start of the PVG service. That was fuel cost - as I'm sure you know, the A340 that US proposed using isn't the most fuel efficient in that size range (on a per ASM basis) and fuel was heading for it's peak in early July when US asked to be allowed to postpone service. As US said in it's motion, "No carrier, however, including US Airways, could have anticipated the rapid and extreme increase in fuel prices that the airline industry has experienced since the United States and China's May 2007 aviation agreement."
As for US' foresight, well...I'll just quote some more from the motion to postpone start of service - "There is no sign that fuel prices will decrease significantly in the foreseeable future." Of course, 3 months later fuel priced did start their decline, eventually dropping below $40 per bbl of oil.
AA filed it's motion to defer start of service citing economic conditions and the prior approval of deferred startup to US, UA, CO, and DL.
Jim