Air China refers to China International Airlines and Shenzhen Airlines refers to Shenzhen Airlines. Although Shenzhen Airlines is a subsidiary of China International Airlines, the two companies are not the same. China International Airlines is one of the state-owned airlines in Chinese mainland, while Shenzhen Airlines is a regional airline in Chinese mainland. There are differences between the two companies in business scope, management structure and brand image. So Air China and Shenzhen Airlines are different.