What information is required to be in an aircraft's flight plan?

A flight plan is a crucial document that provides essential information about the intended flight and is filed with the aviation authorities prior to departure. The correct answer includes the departure and destination locations, the chosen route for the flight, and the estimated time of departure. This information helps air traffic control manage airspace effectively, ensuring both safety and efficiency during flight operations.

The departure and destination are vital for tracking the aircraft's progress and for coordinating with other flights in the same airspace. The specified route outlines the planned flight path, which is important for navigation and maintaining air traffic separation. Additionally, the estimated time of departure plays a key role in scheduling and allowing search and rescue operations to be organized, should they be needed.

Including only the aircraft's registration number, as suggested in the first option, would not provide sufficient information for flight operations. Similarly, merely stating the departure airport and airspeed to maintain lacks critical details like the intended route and destination. Lastly, while knowing the destination airport and pilot's credentials is important, it does not encompass all the necessary flight plan information required for effective flight management.