METHODS OF DETERMINING A RECOMMENDED CRUISE ALTITUDE FOR A FLIGHT PLAN OF AN AIRCRAFT, FLIGHT MANAGEMENT SYSTEMS THAT PERFORM THE METHODS, AND AIRCRAFT THAT INCLUDE THE FLIGHT MANAGEMENT SYSTEMS

Methods of determining a recommended cruise altitude for a flight plan of an aircraft, flight management systems that perform the methods, and/or aircraft that include the flight management systems are disclosed herein. The methods are computer-implemented methods and include receiving flight plan information regarding the flight plan with a flight management system of the aircraft and electronically determining the recommended cruise altitude for the aircraft utilizing the flight management system and based, at least in part, on the flight plan information and a cruise altitude regulation database that regulates cruise altitude within the flight plan of the aircraft. The flight management system includes a logic unit programmed to perform the methods and a display unit configured to display the recommended cruise altitude for the aircraft to a crew member of the aircraft. The aircraft include a fuselage, a wing, an engine, and the flight management system.