What defines an airline tariff?

An airline tariff primarily refers to the agreement between the airline and the passenger concerning the services provided and the corresponding fares. This tariff typically outlines the rules, regulations, and obligations related to the transportation of passengers and the services offered by the airline. It encompasses details like fare structures, penalties for cancellations or changes, baggage policies, and other relevant terms of service.

Understanding this context highlights why the correct answer involves an agreement between the airline and the passenger, as this relationship is fundamental to both the operation of the airline and the expectations of the customer. The tariff serves as a binding agreement that governs the interactions and agreements made at the point of sale, ensuring that both parties are aware of their rights and duties during the travel experience.

The other options presented, while they may hold some relevance in different contexts, do not accurately encapsulate the essence of what an airline tariff is. Tariffs are specifically focused on the airline's relationship with passengers rather than regulatory agreements with the government, internal policies pertaining to operational procedures, or rules governing employee conduct.