The current Flight Management System, CMA-9000, from CMC Electronics -Esterline, does not include a cruise optimization. In the presence of winds, the aircraft fuel consumption is highly affected. If the aircraft experiments head winds, the consumption will increase, and the consumption will decrease in the case of tail winds. The cruise phase is analyzed using genetic algorithms to obtain the maximal optimization possible in the least calculation time. In this article, an algorithm will be defined, that will be capable of selecting an alternative trajectory to take advantage of tail winds in the flight path, and to avoid as much as possible the presence of head winds, to reduce fuel burn. NomenclatureATC = Air Traffic Control FMS = Flight Management System GA = genetic algorithm IAS = indicated airspeed PDB = performance database TOC = top of climb TOD = top of descent