What is the maximum number of aircraft formations participating in an airshow that would not require director's approval?

The correct answer is that a maximum of three aircraft formations can participate in an airshow without requiring the approval of the director. This guideline is established in accordance with regulatory frameworks that prioritize safety and coordination at airshows. By limiting the number of formations to three, unnecessary complexities and potential safety hazards are reduced.

Three formations allow for effective management of air traffic during an event while enabling performers to execute their routines with enough separation to prevent collisions. It ensures that the event can be run smoothly without overextending resources or increasing the risk of accidents that could arise from miscommunication or overcrowding in the airspace.

As for the other options, having more than three aircraft formations could complicate the event management and necessitate detailed oversight by a director to coordinate actions, monitor safety, and ensure compliance with established aviation regulations. Therefore, the answer reflects an essential consideration in aviation safety during public displays.