Which of the following are two requirements for aircraft flying in formation?

In the context of aircraft flying in formation, the correct answer emphasizes two key requirements that are necessary for safe and efficient formation flying. First, "prior arrangements" are essential as they ensure that all pilots involved in the formation flying have coordinated their plans, methods, and intentions before takeoff. This communication helps to maintain safety and predictability in the airspace.

Secondly, the stipulation of "no paying passengers" is significant because commercial operations have stringent regulations that would prevent formation flying. Formation flying is typically associated with military or certain types of general aviation operations where the aircraft are constantly in communication and operating under specific flight rules that may differ from commercial flying.

Understanding the context of formation flying highlights the importance of these requirements. Without prior arrangements, there could be confusion or miscommunication, leading to safety risks. The restriction against paying passengers helps to ensure that all individuals aboard the aircraft are aware of the formation maneuvering and any associated risks.