The aerodynamically shaped, symmetrical cross-sectional profile for the struts or the fairing (7) of struts and service lines in the bypass duct and the core-flow duct of a turbofan engine is defined by a course of the local thickness (T) and a position of maximum thickness (PMT) on both sides over the central chord (C) extending from the leading edge (LE) to the trailing edge (TE) of the strut or fairing (7). In order to avoid flow separations the course of the local thickness (T) between the position of maximum thickness (PMT) and a trailing-edge position (PTE), which is at 95 percent of the chord length, has a first turning point (WP1) with a trailing-edge thickness (TET) and a subsequent second turning point (WP2).