Flight path optimization is designed for minimizing environmental impacts of aircraft around airports during approaches. The main objective of this paper is to develop a model of optimal flight paths taking into account jet noise, fuel consumption, constraints and extreme operational limits of the aircraft in approach. A two-segment approach is obtained as an optimal trajectory. Aircraft alignment on the runway axis with a slope of 3° during the last approach segment is observed and the descent rate is about 1060 ft/mn. This particularly characterizes the continuous descent approach having the potential to reduce noise emission by −4 dB and fuel consumption by −20 % to −10 % during the approach. Measurements of aircraft noise were carried out around Saint-Exupry Lyon International Airport for one year. Because of the suggested trajectory, optimized noise levels are less than the measured and INM values. Optimal trajectory consumes less than the standard trajectory; it can be integrated in the aircraft FMS and used in the autopilot system. This is one of the promising objectives of this research.