Originally Posted by UnitedSkies
No, UA routings are logical. AA's are probably on mileage restrictions, which surprises me that a SAN-ORD-PVG wouldn't bust it.
AA generally makes allowances to the MPM for connecting thru necessary hubs.
LAX-ORD-PVG is a lot less backtracking than one might imagine; looking at the route the great circle mapper, it's really a left turn at ORD, not a complete 180.