That's not a dodecahedron, that's a d12 die with the numbers worn off. Classic case of non-gamers misidentifying polyhedra in the wild. Some mathematician is sitting there, clutching his precious geometric form, thinking "Finally, someone who appreciates Platonic solids enough to bring one on a plane!" Meanwhile, the DnD player next to him is desperately hoping for a critical hit on his saving throw against turbulence.