Thermoplastic for beaks and things

Hello!

I am redoing the beak on a kiwi suit that I am remaking. My original approach using foam and vinyl looked more wolf-like than I would like, and the soft foam was too fragile (it got destroyed by the airline people in transit). I recall seeing folks use thermoplastic before in beak designs. Can anyone recommend a good thermoplastic for beaks, ideally one that can be sourced from someone like TAP Plastics? I already have a heat gun :)

Thanks!