What is the name of the electronic device that maintains control of the aircraft when desired by the flight crew?

The auto pilot is an electronic device that allows the aircraft to maintain controlled flight without direct input from the pilots. By automating various flying tasks, such as altitude hold, heading control, and navigation, the auto pilot reduces pilot workload during flight, enabling them to focus on other critical aspects of flight management and safety.

This system can be engaged when the aircraft is at cruising altitude, and it can adjust to different flight parameters as set by the flight crew. This ensures that the aircraft flies smoothly and efficiently while allowing the pilots to monitor and respond to external conditions as necessary.

In this context, the other options serve distinct purposes. The flight director provides visual guidance on the aircraft's attitude and path but does not control the aircraft directly. The control stick is primarily a pilot's tool for manual control of the aircraft and is not an automated system. The navigation system assists in determining the aircraft's position and guiding it on course but does not directly control the aircraft's flight path. Therefore, the auto pilot is the most accurate answer when identifying the electronic device that maintains control of the aircraft as desired by the flight crew.