What is one method to assist pilots in attaining separation during formation flights?

Issuing advisory information to the formation leader is an effective method to assist pilots in attaining separation during formation flights. In a formation flight, the formation leader is responsible for maintaining the collective position of the group, as well as ensuring safe distances between each aircraft. By providing situational awareness through advisories, such as traffic information, recommended altitude changes, or adjustments to the flight path, the controller helps the leader make informed decisions that enhance safety and maintain separation between the aircraft.

The other options, while potentially useful in a broader context of air traffic management, do not directly address the specific needs of formation flying. For instance, alternate runway options and route deviations could complicate the dynamics of a formation and disrupt the planned flight sequence. Directing pilots to use autopilot may not contribute to the required separation as it depends on the pilots' ability to monitor and manage the positions of their aircraft effectively, especially in a closely flying formation where manual adjustments may be necessary.