airline
[C] Countable
pl: airlines
This term describes a commercial entity rather than the act of flying. It carries a corporate connotation, evoking images of ticketing systems, flight crews, and logistical hubs. It is the standard term used in travel bookings and aviation industry reports. While it refers to the company, it is often used metonymically to refer to the staff or the service provided. For example, saying the airline was rude refers to the employees, not the corporate legal entity.
Countable when referring to the business organizations themselves, such as comparing three different airlines for the cheapest fare.