"We recently discovered that you can bring a car seat on the aeroplane and buckle them in," Teigen told The Cut. "That’s our big strategy now. It changed everything!"
Most airlines will let you check your car seat in for free and not include the weight in your carry on baggage allowance.
However, as Qantas states on their website, car seats need to be approved prior to travel.
"If you do plan to use a car seat, we recommend you contact Qantas to make your booking and no later than 7 days prior to travel, as you will need to reserve and purchase a separate seat and receive pre-approval for your device at least 24 hours before departure. You will also need to show your device to our airport staff on the day of travel, including at check-in," the website says.
"If your travel includes airlines other than Qantas, you will need to contact those airlines directly to gain approval to use your device, and other airlines may have different rules and requirements."