If you're planning on flying with your pet, make sure you know about United Airlines Pet Policy before you go to the airport. United Airlines only allows pets in the cabin on certain flights, Depending on animal breed and size of your pet. If your pet is too large to fly in the cabin, they can be shipped as cargo, but there are a few things you need to know about this process. If you have any questions about our United airlines pet cargo policy, please don't hesitate to contact us.