Air carrier is a term used to refer to a company that operates commercial flights for passengers and cargo shipments. There are several synonyms for the word "air carrier," which can be used interchangeably. For instance, airlines are a popular synonym for air carriers, and there are different kinds of airlines such as regional airlines, low-cost carriers, and legacy carriers. Aviation companies also refer to businesses that engage in air transportation of goods and people, while air service providers offer more comprehensive air services. Other synonyms include air taxi, air freight, and air cargo service providers. Ultimately, whatever term you use, the underlying meaning remains the same - a company that operates flights.