Certainly a bathroom has to be included, you can't lock people in a tube in the sky and then not let them pee.

But I believe Ryanair considered trying not to use seats at one point.

Actually you can do exactly that, at least in the US. I've been stuck on a plane more than once and told I couldn't use the restroom

That sounds unlikely - did they give a reason (e.g. toilet cannot be used when the fasten seatbelt light is on during turbulence/landing/take-off)

The reason was because they said so.

Keep in mind, I also had a flight attendant tell me that using Zoom on a plane is a felony.

Which airline(s) was that, so that we can avoid them?

Then they will have to hire cleaners, because I will shit and pee all over the seat.

I've never personally seen someone do that but I have heard stories of this happening before.

I have incontinence, so I either wear diapers (still going to pee and defecate regardless), or I have access to the bathroom in time. If I wear diapers, there is going to be odor contamination in the area. It is bad for others, and for me, and their business too, I assume. Depends on the length of the trip; I try to limit fluid intake to zero before I go outside.

Ryanair also considered charging for bathrooms.

Although in both cases, it's hard to tell if they were serious, or just doing PR.

It’s not hard to tell at all.

At peak season every year, O’Leary says something crazy like they are going to charge for the bathroom, or charge fat people extra, or get rid of arm rests, or have standing room only. The tabloids run the story, and always mention how cheap the flights are, including whatever the cheapest deal at the moment is.

It’s very, very obvious advertising. The tabloids go along with it because it makes people angry, which drives traffic.

Seats are not included in all bus or train tickets :)

The only reason the seat is necessary on a plane is for safety.

I'd include air and a seatbelt

in a more civilized time there would be a bit more than that.

Up until 1978 there was a lot more than this in the US. This is where we see photos of carts that brought prime rib to passengers and people in suits toasting with champaign glasses and there was so much space in the aisle that you could pass by service carts. It was like that because airlines were extremely regulated and not allowed to compete on price. So they competed on what was included. The result was photos of "a more civilized time" but also that almost nobody could afford to fly.

I've probably paid more for a single beer than some of my flights.

Also business flights are kinda affordable if you really shop around.

I’m not talking about steaks. I’m talking about basic human rights, like a glass of water and access to a restroom.