Commercial aviation refers to the use of planes for the transportation of people or goods, typically on a for-profit basis. There are several synonyms for this term, including civil aviation, air transportation, scheduled air transportation, passenger aviation, and airline industry. Each of these phrases is an alternative way to describe the same concept, and they may be used interchangeably depending on the context. Other related phrases might include aircraft transportation, air travel, or aviation business. These synonyms help to convey the breadth and importance of the aviation industry, which plays a critical role in modern transportation and commerce.