 The International Civil Aviation Organization sets international standards and recommended practices for national authorities to base their regulations on  The national regulatory authorities set standards for airworthiness, issue certificates to manufacturers and operators and the standards of personnel training.Every country has its own regulatory body such as the Federal Aviation Authority in USA, DGCA (Directorate General of Civil Aviation) in India, etc.The aircraft manufacturer makes sure that the aircraft meets existing design standards, defines the operating limitations and maintenance schedules and provides support and maintenance throughout the operational life of the aircraft.