民航售票系统，系统以菜单方式工作，航班信息录入功能(航班信息用文件保存)－－输入，航班信息的查询，浏览功能－－输出，订票业务，退票业务 -Civil aviation ticketing system, the system menu the way to work, flight information entry function (flight information with file)- input, flight information queries, navigational