Indeed. If I owned one, for sure he’d be named “General Woundwort”.
They’re definitely pressurized, as they are inside the body of the plane. The dividers between the cargo hold and the passenger hold aren’t airtight. They’re supposed to be warmed appropriately. From what I understand they aren’t lit, which can be frightening for some animals.
You win the thread!
I also suspect that the normal airplane noises are quite loud down there. Landing gear deploying or being retracted, etc. Also even though animals are confined in a hard-wall crate, they’re not seatbelted into a seat like we are, so turbulence is likely to toss them around a bit. Not a nice experience, that’s for sure.
I used to volunteer with a dog rescue that brought dogs from Spain the the USA, trips not unlike the bunny’s flight in the OP. Some would mess their crates but some would hold their bladder for the entire 8 - 10-hour flight. I’ve seen male dogs pee for over 3 minutes straight after we let them out of their crate at the destination airport.
James Stewart has a new pal in the afterlife.
Dewey Finn:
Well, now the rabbit can be with Michael Jackson.
Okay… I lol’ed. 
He wasn’t so unusual, most rabbits are 4 footers.
What was the inflight meal ?
Picturing Bugs Bunny saying, you know of course this means war
Except the ones who get them cut off. Not so lucky for the rabbit.
I don’t think that all of the cargo holds on the planes are pressurized to cabin pressure. Only some of them are. You’ll get extreme temperature problems. I’ve been on a flights that was re-routed because a dog was in the wrong hold, the pilot realized it and we landed to move the animal before he was harmed. Fortunately, everyone on board took that well. Sometimes people don’t.
Animals also sometimes do not travel well, even if they are in the correct hold, in their crate, with appropriate bedding and all their own materials. It’s possible the experience itself terrified him to death (rabbits are not bold animals) or that he had another health issue. Generally, the airlines will want a health certificate before travel to try to control for this.
I guess if you’re a celebrity collecting a celebrity rabbit you might want to spring for a private plane (not really kidding on that - there are animal transport services).
The seller said that the rabbit had a health examination three hours (days?) before the flight.
Maybe the trip had something to do with the rabbit’s death, but sometimes people die on planes too. Everything dies eventually and sometimes it just happens on a plane.
This would be harder than pressurizing them. It’s easier to just use the skin of the plane than build a heavy and expensive pressure barrier into the floor of the cabin.
Agatha Christie Death in the Clouds
The rabbit did it. A Harecule Poirot Mystery
I don’t recall the Raymond Chandler quote. Something like, “The English don’t write the worst novels, but they write the best bad novels.”
This linksays that 16 people die on airplanes in the average year, but that this information is based on flawed data. The number of rabbit deaths annually on planes is unknown.
I’m pretty sure pressurization and climate control are different issues - pressurized yes but also potentially really cold.
That part aside, what interests me is that the seller claims good health declared on the rabbit 3 hours before takeoff, but she refused United’s offer to pay for a 3rd party necropsy. I find that very suspicious on the seller’s part. If I were her, and as confident as I claim on the rabbit’s health, I would absolutely want the necropsy.
Looking at the photograph in the OP’s link.
Noticing how easily Ms. Edwards is holding a 50 lb. rabbit at arms length, I just did the same with a 50 lb. dumbbell.
Either the rabbit’s weight is being grossly exaggerated, or that’s one amazingly strong woman.
Elaine Dickinson: “Well, we had a choice of steak or fish.”
Well now, wasn’t that a waste of money