Originally Posted by
heegaardfloer
I recently flew NRT -> SFO (8/19) on (paid) Premium Plus. However, I noticed a strange 2/4/2 economy plus configuration for my flight the next day SFO-MUN. I quickly snagged one of the seats and it turned out to be a premium plus seat. This led to the question: on which routes is premium plus equivalent to economy plus? Or maybe it is random...
Welcome to FlyerTalk!
The closest you can get to E+ = P+ is if you fly the 787-10 from SFO/LAX to EWR. However, aircraft types aren't guaranteed, so even that one isn't guaranteed.
Other than that, it's random: if you're on a non-P+ route, and the plane assigned to your flight happens to have a P+ cabin, then you get free P+. However, the reason that they're not selling P+ on every applicable international route is that they're not willing to guarantee plane assignments like that.