1. A computer-aided method suitable for assisting in the design of an aircraft by providing dimensioning aerodynamic forces, skin values or values distributions around an airfoil corresponding to an aircraft component in transonic conditions inside a predefined parameter space by means of a reconstruction of the CFD computations for an initial group of points in the parameter space using a reduced-order model, generated by computing the POD modes of the flow variables and obtaining the POD coefficients using a genetic algorithm (GA) that minimizes the error associated to the reduced-order model, characterized in that it comprises the following steps: a) Decomposing for each flow variable the complete flow field (CFF) into a smooth field (SF) and a shock wave field (SWF) in each of said computations for an initial group of points; b) Obtaining the POD modes associated with the smooth field (SF) and the shock wave field (SWF) considering all said computations; c) Obtaining the POD coefficients using a genetic algorithm (GA) that minimizes a fitness function defined using a residual calculated from the Euler equations and boundary conditions; d) Calculating said aerodynamic forces, skin values or values distribution for whatever combination of values of said parameters using the reduced-order model obtained in previous steps.