What is the primary responsibility of an aircraft operator?

The primary responsibility of an aircraft operator is to operate and manage aircraft. This encompasses a broad range of duties, including ensuring that the aircraft are maintained to safety standards, conducting pre-flight checks, adhering to aviation regulations, and managing flight crew operations. This role is crucial for the safe and efficient operation of flights, as it involves not just piloting the aircraft but also overseeing the various operational aspects that ensure passenger safety and comfort.

The other options, while related to the airline industry, do not reflect the core responsibilities of an aircraft operator. Selling airline tickets pertains more to the commercial aspect of the airline's operations rather than the actual management or operation of the aircraft. Providing in-flight meals is a service function that is important for passenger comfort but does not encompass the overarching responsibilities of an aircraft operator. Scheduling flight times is a logistical responsibility that may be part of the broader management of airline operations but is distinct from the direct responsibilities of operating and managing the aircraft themselves.