What best describes the term "ancillary services" in air travel?

The term "ancillary services" in air travel refers to additional services offered by airlines that enhance the passenger experience beyond the basic flight operations. These can include a wide range of services such as baggage handling, in-flight meals, entertainment options, priority boarding, seat selection, and airport lounge access. Airlines often charge extra fees for these services, and they can significantly contribute to the overall travel experience, making them an essential aspect of airline business models.

While basic flight operations are crucial, they do not fall under the category of ancillary services, as they involve the primary function of transporting passengers from one location to another. Essential travel documentation is necessary for travel but is not considered an ancillary service since it relates more to compliance with travel regulations. Cockpit engineering assessments are technical procedures related to aircraft safety and operation rather than services provided to passengers.