関連ワード:  what are the 2 types of airplane engines    what are the 2 types of airports    what are the 2 types of air pollution    what are the 2 types of airworthiness directives    what are the 2 types of air    what are the 2 types of air masses    what are the 2 types of aircraft    what are the 2 types of air supplying respirators    what are the 2 types of air pressure    what are the 2 types of aircon