Originally Posted by Unitedloyalflyer

yep KOA-DEN-IAH

These were also both Z fares I was seeing. A Z through DEN was 50% higher than a Z through LAX (I booked my wife on miles, and that was somehow the best mileage price, the cash and miles prices were not in synch)

Originally Posted by dkc192

Was the prevailing coach fare the same for both routings? Domestic premium cabin fares are often priced as a differential from the corresponding lowest coach fare, so that can often explain the fare difference when booking into the same fare bucket.

Originally Posted by Kacee

UA uses differential premium cabin pricing, based on an underlying economy fare basis, so a Z on one flight is not necessarily the same as a Z on a different flight (or even a Z on the same flight based on changing inventory). One fare could be based on an L while the other is based on an H, for example. That will create a large pricing disparity.

Bottom line: airfare pricing is complex and snap conclusions about "why" are often inaccurate.