What defines an Unmanned Aircraft (UA)?

An Unmanned Aircraft (UA) is defined as an aircraft that operates without a human being physically present on board. This definition encompasses various operational methods, including remote control, where a pilot controls the aircraft from a distance, and fully autonomous operations, where the aircraft navigates and completes its mission without any human input.

This definition highlights the key aspect of UAs: the absence of a pilot onboard, differentiating them from manned aircraft. By not having a human physically present, UAs can function in a variety of scenarios including those that may be unsafe or impractical for manned flights. This foundational understanding is critical for grasping the operational, regulatory, and safety considerations involved in flying UAs.

In contrast, the other choices provide limited or misleading definitions. While "autonomously" could describe how some UAs operate, it does not account for all UAs which might still have a pilot controlling them remotely. Similarly, "under remote guidance only" implies a restricted operational mode that excludes autonomous functions.