Originally Posted by
bniu
from recent reports, I know CX YVR-JFK doesn't pre-clear since it's not worth CX's time to deplane all the continuing passengers and make them go through immigration in YVR when they can easily just cross immigration at JFK.
I guess you are referring to TWOV.
http://www.cic.gc.ca/english/departm...index.asp#tphp idtphp
However, OP is referring to ORD/LAX/DFW, which is a different story, ie. no CX available.