Originally Posted by
findark
To actually sit in a true Premium Economy cabin (Premium Plus on UA metal), you do indeed require a primary rbd of O, A, or R. These fares have an 'O' in 7th position.
For example, compare this "Economy Plus" fare on SFO-EWR:
I don't understand why this isn't a Premium Economy fare based on the fact that it says "PREMIUM ECON OW APEX NON-REFUNDABLE". I think it's the FARE TYPE that matters (ZOA in this case) and not the primary booking code.