Pets are placed in “hold 5”, at the rear of the plane. It is part of the cargo area underneath the cabin, but it is separated and it is heated. It is kept at the same temperature and pressure as the cabin, since the captain is notified of animals on board, and will make sure of this.

On a commercial aircraft, a dog's seat depends on its size, function, and the airline's policy. Small pets (usually under 20 lbs) are permitted to travel in the cabin, but they must sit in an airline-approved carrier that fits entirely under the seat in front of you. This means they cannot sit on your lap or in a spare seat you've purchased for them. The only exception to this is for Trained Service Dogs, which are legally allowed to sit on the floor at your feet, in your footwell, or sometimes even in your lap if they are small enough (though they cannot block the aisle). For larger dogs, the primary option is the climate-controlled cargo hold. Modern planes have dedicated, pressurized sections for live animals where they are kept in a sturdy, IATA-compliant crate. These areas are separate from the luggage, kept dark and at a consistent temperature to minimize stress. While some private jets or boutique airlines (like BARK Air) allow dogs to roam the cabin, on major carriers, your dog will be either under the seat in front of you or safely in the hold.