Perfect fit.
I bought a cheaper, brandless product off an online shop. Found out Flowzoom to be the original design so I decided to buy one and it was the perfect fit for me. I bought the Grey-Large size AIR Pillow because of the "Walrus". It's the best position for my neck on the plane and never experienced stiffness at all. Perfect for economy seats, feels like first class. I hope they make even more comfortable, upgraded pillows in the future - better, ergonomic designs, or a sturdier, more defined chin support for economy class travels like planes and trains where the seats are too narrow and your only option is to sit the most upright position, your neck deserves all the love and comfort. Could a medical-grade neck brace/support be transformed into a comfortable travel pillow? That's one idea.