Which of the following best defines the term "Observer" in the context of aviation?

In the context of aviation, an "Observer" refers specifically to someone who holds authorization to occupy a jumpseat during a flight. This role is typically designated for individuals such as flight attendants in training or other crew members who are not actively performing their duties but are present to gain experience and insight into flight operations.

The jumpseat is a designated seat for crew members that allows them to observe flight operations and assist if necessary while still adhering to safety and regulatory protocols. Being authorized as an observer indicates that the individual has met certain criteria and has the permission to be in that particular seat, distinguishing their role from that of a regular passenger or other personnel on the flight.

The roles of a flight attendant in training and a captain are different, as they carry specific responsibilities related to flight safety and management rather than merely observing. A passenger on the flight, meanwhile, does not have any authorization that qualifies them as an observer in this context. Therefore, the definition of "Observer" aligns best with someone authorized in the jumpseat.