As one of the largest airlines in China, China Southern Airlines has a wide range of business and a number of secondary institutions, including ground services, air freight and aviation maintenance. Compared with the headquarters of China Southern Airlines or the first-level departments, it is relatively easy for the second-level institutions to join the job, because the second-level institutions usually need more employees to support and perform various tasks. Moreover, the recruitment process of secondary institutions is relatively simplified, the competitive pressure is relatively small, and the entry threshold is relatively low.