1. Generally, within 3 years from the date of issue, airlines will keep relevant information, and some have their own ticketing databases, which can be kept permanently.
2. China Airlines include: China International Airlines, Shenzhen Express Airlines, China Southern Airlines, China Eastern Airlines Group, Hainan Airlines, Shanghai Airlines, Xinjiang Airlines, Sichuan Airlines, Xiamen Airlines, Changan Airlines, China Cargo Airlines, China General Airlines, China Post Airlines, China United Airlines, China Xinhua Airlines, East Star Airlines, Guizhou Airlines and Huaxia Airlines.
3. The air ticket inquiry system is a data system of major domestic airlines based on TravelSky, which is a software embedded in the website and used by air ticket agents to inquire, book, pay and process orders. It is not only a platform that can be connected with civil aviation hosts for reservation operation, but also puts forward the concept of business green channel in addition to the functions of address sharing, user authentication and information recording.