The goal of this thesis is to improve the wave drag estimation techniques in the aircraft conceptual design. Based on the most relevant methods, among those developed in the past $60$ years, three methods are proposed as an attempt to include more design variables and improve the accuracy of the wave drag prediction. The proposed methods include the use of supercritical airfoils and the cross sectional area distribution of the aircraft as port of the wave drag estimation. The proposed methods are compared to experimental drag data, available in the literature, of four high-subsonic conventional transport aircraft. An accuracy analysis is performed evaluating how well each method predicts the drag divergence Mach number, the wave drag at Mach number 0.8, and how well the predicted curve fitted with the experimental data. The analysis led to the conclusion that the results of the Delta method shows better agreement with the experimental data than the proposed methods. The state of the art techniques and the proposed methods have been implemented and integrated into a conceptual design tool, as a new module. The module functionality, including its settings, inputs, outputs and functions are also described in this document.