Originally Posted by
sbm12
The PMUs (the DL name for SWUs) require a ticket purchased in one of the top three fare buckets (Y/B/M, I believe) and upgrade into restricted inventory (I, I believe).
Yes, sort of. It is Y/B/M for international, but domestic flights (including Hawaii) are upgradeable from other classes - I think K and above. Bear in mind, also, that the cost of an M fare, in my experience, tends to run about the same as a CO fare + upgrade fee, so your out of pocket cost is not any higher. Of course, if you don't get the upgrade on DL, you don't get a refund of the extra money... You do get 150% MQMs and RDMs for Y/B/M fares, which is a plus.
Also, the fare classes are G, for domestic and Z for international. Availability depends on the route, it seems, but seems neither terrible nor great.