Disclosed is a lightweight honeycomb structure that comprises a top panel (34) and bottom panel (32) and a large-celled honeycomb layer (36) disposed between the top and bottom panels. The honeycomb panel structure according to the present invention can be used in such applications as a sound-absorbing payload shroud for launch vehicles, flooring and walls in aerospace applications, aircraft wings and in structures that will be exposed to high heat. Additionally, a method of making a honeycomb structure of thermoplastic material is disclosed.