Aerated composite materials in the shape of a three-dimensional objects and methods of producing the same. The composite comprises a thermoplastic biodegradable polyester mixed with reinforcing agents selected from particles of woody materials having a smallest dimension greater than 0.1 mm. The composite material further comprises regions of elasticity formed by incisions which upon stretching will yield open pores. The incised regions will also provide for flexibility or semi-rigidity in at least one dimension. The material can be used in comfortable splints and circumferential casts.