This doctoral theses deals with the application potential of natural fiber composites in aviation structures as the overriding goal, and in helicopter structures in particular. This goal will be approached using various empirical investigations with flax composites. Tests for the analysis of structural mechanics were carried out and evaluated. Hereby existing material models were combined and applied within the framework of a finite element method. Furthermore, several critical aspects of flax, such as hydrophilicity and stiffness nonlinearity, as well as beneficial aspects, such as eco-efficiency and damping, were analyzed and evaluated regarding aviation needs.