SFO-SNA is not that hard at all, which is one of the reasons I don't believe for a minute that SNA has an unusually high number of UA elites. Nothing like ORD. Heck, I've had a harder time upgrading SFO-PHX.

I fly SNA-SFO often (bizarrely, SNA-SFO->Asia is cheaper than LAX-Asia). The morning flight (e.g. UA209) I'm pretty sure over half the plane boards in Group 1 most of the time, even on Tuesday/Wednesday/Thursday. I'm in Group 2, and it seems relatively sparse compared to Group 1 and Group 4, so I doubt it's silvers.

SNA-SFO morning flights are probably pretty tough, judging from what I see in the gate area. SFO-SNA might be easier? I've also flown daytime mainline flights recently which are rarely full (maybe 60-70% load?) so I'd be willing to bet those are easier to clear with high status. The upgrade list the last SFO-SNA I've flown was maybe 20 or so names, and top six cleared?

I've definitely flown A320s into SNA. I've never sat upfront before though, so I can't comment on the FC seating.

Yeah I'd guess this as well. People living in Irvine seem disproportionately wealthy enough to just pay for first class, and given how cheap JetBlue is, if I lived west of SNA (e.g. Fountain Valley), I'd opt to fly out of LGB. I can't speak much for business travel though. I'm not sure which local businesses would pay for domestic first over economy.

In that case, couldn’t your claim apply to SFO too?

20 on an upgrade list to me implies a very elite light load. I feel like most lists I see are 50+. I stand by my view that SNA is one of the most elite light airports in the network. And I don't mean total pax, I mean as a percentage.

I'd love to see data if anyone has it.

Ah, sorry, I forgot to mention that last flight was one of those random midday light-load flights (ex-SFO ... maybe Disneyland traffic?). Pretty sure there were fewer than 100 people on that plane.

I can't say I've flown from that many non-hub airports, so the most I can say is "it feels like SNA has way too many people boarding in BG1."

A hypothesis w no data...
Kettles in orange county purchase premier access (I mean, if anyone was going to pay for that, it would be SNA people lol)

Premier access only gets you into BG2 though, no? (again, I wouldn't know -- I don't pay for premier access)

As for "hypothesis with no data" sure, I concede that the several SNA-SFO RT flights I've taken over the past three months aren't exactly qualitative "hard data" but I'd argue you haven't exactly provided data to the contrary either.

Look, I'm not saying SNA is particularly elite heavy. What I'm saying is of the distribution of elites, from my experience so far: it seems exceptionally weighted towards Plat and above. ("over half the plane boards in group 1") -- I have no frame of reference as to whether that is considered elite heavy or not, as the only hubs I regularly fly out of are SFO and IAD. :)

I've been a 1k out of SNA and ORD for over a decade and flown to all over from there on a regular basis. I'm not sure of data, but I can say for sure that the biggest reason it is hard to UG the ORD-SNA routes is the almost entirely 737 cabins on the route. Only 12 seats and from talking to flight attendants over the years, the vast majority are purchased F or GS on business days. The amount of times I have cleared CPU as a 1k on that route is very minimal. You better use an instrument. UA has also cut flights there and AA usually has at least 1 more route a day and their planes have 16 in F.
Good luck on this one, but I'm not sure UGs here are really any more difficult on UA these days than any other lengthy route. Try finding a flight over 3 hrs on UA that is not at 6am on Sat or 9pm on weds to use a RPU

IME, SNA is very heavy on resident elites. So you see extremely long upgrade lists and G1 lines for flight times that correspond to someone whose home base is SNA flying, and relatively light in comparison at other times. SFO/SNA can be an easy CPU or it can be impossible, and it depends a lot on time of day and week.