The paper describes results of a comprehensive experimental and numerical investigation of the aerodynamics of miniature trailing-edge devices (MiniTEDs) on a supercritical airfoil at transonic speeds. The influence of MiniTEDs on the two-dimensional airfoil flow and on the aerodynamic coefficients is presented in detail for the Gurney flap, the split flap and the divergent trailing-edge. The influence of geometry parameters is discussed for the Gurney flap height, the split flap deflection angle and the MiniTED position, as well as for different types of perforation. The use of MiniTEDs as adaptive elements is presented for drag-optimal operation and is compared to the performance of a flexible trailing-edge. The influence of different freestream parameters is discussed for the Mach number and the Reynolds number.