【 Expandable Design 】 This pet carrier with an expandable back design gives your pet more space to rest and increase air circulation, allows your pet to move around more comfortably and reduces the anxiety. Airline approved? Each airline sets their own specific requirements, so it is advised to check with your airline of choice. 【 Ventilation & Visibility 】 1, The top of the dog backpack can be open, for your pet to stick their head out off, you can zip the cover on the mesh for breathability and visibility or you can snap on the shade cover to protect from the sun. 2, Three-sided acrylic sheet design can provide good light transmission. There are four venting holes + venting net design on the left and right sides to ensure air circulation and no sultry heat. 【 Adjustable Shoulder Strap 】 Widened design, adjustable shoulder pad to help reduce load and increase comfort, two retractable buckles on the top and bottom of the cat backpack to prevent shoulder strap deviation and maintain the stability of the pet puppy carrier.