Methods and apparatus for providing trajectory planning for an aircraft based on constraint processing are disclosed. The method may take into consideration the dynamic or real-time operational and environmental factors, and utilizes constraint processing to provide trajectory optimizations between the end points of the flight. The trajectory planning method may be performed utilizing a computer or processor onboard the aircraft. The method may include receiving a starting location and an ending location for a phase of flight of the aircraft; receiving a set of constraints from multiple systems and sensors for the phase of flight of the aircraft, wherein operations of the aircraft during the phase of flight are subject to the set of constraints; and analyzing the set of constraints to determine an optimal trajectory between the starting location and the ending location, the optimal trajectory is determined based on compliance with the set of constraints.