A STAR is designed to facilitate transitions between which of the following?

A Standard Terminal Arrival Route (STAR) is specifically designed to facilitate the transition between the en route phase of flight and the terminal area. This structured route helps guide aircraft in a safe and efficient manner as they approach an airport, reducing the workload for air traffic controllers while also ensuring a smooth flow of air traffic.

By providing a set path for aircraft to follow, STARs help to manage the arrival sequence effectively, ensuring that incoming flights are integrated seamlessly into the traffic pattern of the terminal area. This is crucial for maintaining safety and efficiency, particularly in busy airspaces where numerous flights may be arriving at the same time.

The other options do not accurately capture the specific purpose of a STAR. The airport departure and recovery phases, final approaches and takeoffs, and the transition between instrument and visual flight rules address different aspects of flight operation that are not the primary focus of a STAR.