<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by UAEmployee:
The codeshare flights are also (usually, except in the case of MX) timed to meet incoming and outgoing banks of two or more carriers at a given airport much better than if the airlines weren't codesharing. Look at UA/AC ORD-YYZ. Together, they split the market and you end up with hourly service (better for the pax) and fuller planes (better for UA and AC). If we didn't have code share service we would either have to add frequencies (less profitable, but better for the pax) or disservice the pax by not having as much choice, thereby probably losing more pax to AA.
</font>
UA & AC can coordinate the timing of their flights without selling flight segments to passengers under a codeshare flight number masquerading as the other carrier.