Due to their high strength and stiffness at comparatively low weight, lightweight construction materials such as fiber-reinforced plastics (FRP) are used in a variety of technical systems. The areas of application range from aerospace and renewable energies to the automotive sector, which is gaining increasing importance. The non-destructive testing via air coupled ultrasound is a decisive factor for the detection of production and operation induced defects. As a result, it is possible to examine components regarding possible defects without contact or coupling medium. Using carbon fiber reinforced plastic tubes with different geometries it was possible to demonstrate the suitability of air coupled ultrasound for defect detection. For this purpose, guided waves were contactlessly excited in the tube, which circumferentially propagated along the components' cross-section. Based on the amplitude and phase characteristics of the waves, defects could be detected in different axial and circumferential positions within short inspection times of a few seconds. The developed testing method is automatable and hence offers a high potential for future quality control in serial production.