What is the latest time passengers without check-in baggage may proceed to the boarding gate for domestic flights?

For domestic flights, passengers without check-in baggage typically need to arrive at the boarding gate well in advance of departure to ensure a smooth boarding process and time for any necessary security checks. The correct answer indicates a cutoff time of 15 minutes before departure. This time frame allows for efficient boarding and aligns with standard airport policies, which often emphasize the importance of having passengers at the gate with sufficient time before the aircraft's scheduled departure.

This timing is critical as airlines need to effectively manage the boarding process and ensure that the aircraft can depart on time. If passengers wait until the last minute to arrive at the gate, it can lead to delays that affect the overall flight schedule. Therefore, a 15-minute cutoff for boarding without check-in baggage is consistent with industry practices that help to maintain punctuality and operational efficiency.