I fly SJC-LAX at least once a month and have found that UA, WN, and AA usually price out at about the same for advance purchase fares ($90 to $125), but that WN often has a very slight edge for last minute purchases (you'll never pay more than $95 each way). In terms of service, reliability, and convenience, AA wins hands down -- even though I'm primarily a UA loyalist, I will never again fly them to LA as driving is often faster, terminal C is a dump, and there is no E+ on shuttle flights. WN is pretty reliable, but their seat yourself system isn't compatible with my just in time to the airport policy. Also, WN checkin is always a headache.