The fare classes are nested-ish.

Meaning when the GS pulls the P, an R disappears?

Possibly. I doubt the exact relationship is so simple or well-understood.

Yup, and it shows UAs limited reach when faced with competition like at SEA. With VX, AS, and WM all flying the market, they are just doing the minimum to keep some of their elites from defecting on this route, and then running the larger planes to hope to feed to international flights.

Yes.

It appears so, but no one really knows. But if there are two available spaces, giving one out as a P only leaves one, and if it was P=2, R=1, you can bet that R will = 0 when it clears. Certain buy ups clear into P (or someone can walk up and buy the F seat), so UA wants to keep those buy ups going rather than giving away the seat.

Battlefield upgraded on this past Wednesday's midday DCA->ORD. The plane wasn't packed, and being midweek, very light on business travelers (plane flew with 14/16 F full), but this was my first CPU since '11 so I was happy for that (even though the flight was only ~90 minutes long).

Except more than 50% of my plane connected to the SYD flight, as did I. So they run a small A320 and most of it goes international. Of course the flip side of the coin is they could have run it as a CRJ200 which now appears on SEA-SFO.

-RM

I am Gold flying on a K fare, just scored a battlefield CPU on a IAD to LAX, a 738 no less...wow this never happens :-) Only two pax remaining on the upgrade list at T-15min

As a general rule, yes the fare buckets are nested.
Even selling an F seat can knock P and R down a seat. It's Yield Management (YM) in its simplest form. The sale of an F fare indicates a demand for F on that particular flight. If paid F is in demand, then why hand out another P or R upgrade ?

That's the immediate effect. Afterwards, YM will follow-up and may readjust P and maybe R back up by that one seat.
High level logic & an over simplified example ...
based on history, YM thinks 6 F seats will go unsold. So it starts selling the flight at F9 P6 R5
The 9 in F9 being the max number displayed (in some cases, IE: partner flights, the max could be 7 or 4 or ??)
Internally, the F9 displayed might be F16 (737-800). Selling an F seat could behave differently when the internal number is F16 vs F9.
If selling the F seat initially lowers P/R by one seat, YM analysis later on may say: "no, that's one of the 10 seats I expected to sell, I still expect 6 F-class seats to remain open, so restore availability to P6 R5.

On the other hand, if YM thinks it's already sold the 10 expected F seats, thus the current sale is unexpected, then the upgrade buckets will remain at P5 R4.

And many folks don't realize that YM is dynamic. That unexpected sale might make YM think more unexpected sales are around the corner thus lower P/R by more than the one seat sold. Initially, YM thot all but 6 F seats would be sold, but that initial thot is NOT set in stone. That initial availability will go up and down as YM evaluates/re-evaluates 1000s of variables.

Thanks! With the number of daily flights, scheduled out 330 days, this process must be incredibly complex. Is there some dude looking at individual flights on a daily basis or is it totally automated (or, more likely, some mix thereof)?

There is definitely something fishy going on with CPUs right now...

Flew COS-BOS-COS with my wife last week. I was on a mixed fare V&T ticket while my wife was flying on miles - 2 separate PNRs. I should mention that my wife's flights were booked into Business (IN) bucket so she was already sitting up front while I played the CPU lottery.

On the BOS-DEN return (a 739 w/ 16 F seats), my wife sat next to a Gold who admitted to her that he was really surprised that he got upgraded. He did not use any instrument or miles and was CPU'd. I sat in 21C and ended up #9 on the UG list (Nobody boarded when the GA called GS so I doubt there were that many with higher status ahead of me).

For the short DEN-COS hop (CR7), my wife was in 2C and I was #1 on the UG list with 2 empty seats. I sat in 3B. I monitored the United app expecting the GA to come on board and move me up - it never happened. A guy boards last minute (he missed his earlier flight) and the GA just waves him into 1C. 2A went out empty. Apparently the GA never processed the UG list at all. Not a big deal for a 20 min flight but it irritates me when the process isn't followed.

Leads me to start questioning what other things aren't happening that should be?

Not confidence inspiring at all.

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Somethings definitely going on. How can flights that are nearly completely empty in F not clear a 1K at T-96 or T-72. We are now at T-60. No upgrades processed on the whole flight.

This is crazy.

I might be misreading this, but 35% is not elite heavy. I just flew a BOS-ORD flight on a 738 that had over 100 elites on it. And I've seen plenty of ORD-DEN flights with UG lists approaching the 75-90 numbers.

Totally unacceptable. Please PM all the flight details to our UAInsider