Methods and systems for controlling the flight of aircraft are disclosed. An example system includes a flight management computer to receive a first time of arrival at a first target waypoint of an aircraft and a second time of arrival at a second target waypoint, determine a first set of cruise speed and descent speed pairs corresponding to the first time, the first set satisfying the first time, determine a second set of cruise speed and descent speed pairs corresponding to the second time, the second set satisfying the second time, select a cruise speed and descent speed pair from the first set or the second set, determine an aircraft trajectory that satisfies the selected cruise speed and descent speed pair, and cause at least one of: 1) the aircraft to travel along the aircraft trajectory or 2) the aircraft trajectory to be displayed.