What does boarding refer to in airline procedures?

Boarding in airline procedures specifically refers to the process of allowing passengers to enter the aircraft before takeoff. This is a critical step in preparing for a flight, as it involves various activities such as checking boarding passes, ensuring passengers find their assigned seats, and stowing carry-on luggage.

During boarding, airlines typically announce the process in stages or by group numbers to organize the flow of passengers efficiently and maintain order. This ensures that everyone can board the aircraft in a timely manner, thus facilitating a smooth transition from the terminal to the aircraft.

The other options relate to important aspects of flight preparation and operation, but they do not accurately capture the essence of what boarding entails. For instance, waiting for departure is part of the overall process of flight readiness, but it happens after passengers have already boarded. Moving luggage onto the aircraft is an important logistical step, but it is separate from boarding passengers. The official authorization to fly, often referred to as "clearance" or "departure clearance," is a procedural requirement that occurs after boarding and focuses on regulatory compliance rather than the boarding process itself.