Make sure to remember heat in cars. Even with windows rolled down heat is trapped in a vehicle much like a greenhouse. It takes only minutes for the interior of a car to become much hotter then the outdoor temperature. When exposed to such heat a pet can suffer heat stroke, a very life-threatening condition. Air It is important to always check the airlines pet policies.
Different airlines have different carrier size allowances.
Most likely your pet will be placed in the cargo area which is not heated or cooled regarding outdoor temperatures. It is important to keep this in mind regarding your pets comfort. Check with the airlines regarding smaller pets, some airlines now allow smaller pets to travel in the passenger cabin. Most vets don't recommend sedating your pet for travel. The reasoning for this is due to pet injury from falling after sedation, a pet's inability to adjust to temperature changes and blood pressure.