I’ve never done it.

Do you buy it a ticket, in which case you would just set the crate on the seat, right?

Do you pay some sort of extra fee, but it’s classified as carry-on baggage? If this, shouldn’t it be treated as any other carryon, ie held in your lap but stowed during takeoff and landing?

I’m not talking about teacup poodles or other toys here, I’ve seen them on owners’ laps in backpacks or purses or whatever.

Is it possible for a dog in a larger crate to be loaded into cargo? I see people picking up crated dogs at baggage claim, or at least I have once or twice. I remember thinking, “I thought the baggage compartments weren’t pressurized, wonder how they did that?”