Which body is primarily responsible for establishing certification requirements for aircraft operators?

The National Aviation Authority (NAA) is primarily responsible for establishing certification requirements for aircraft operators in a specific country. Each nation has its own NAA that oversees the aviation industry within its jurisdiction, ensuring that operators comply with national regulations for safety, operational standards, and personnel qualifications. The NAA is tasked with the certification of airlines and other aviation operators, which includes reviewing safety practices and issuing licenses necessary for their operations.

While the International Civil Aviation Organization (ICAO) sets global aviation standards and recommends practices to which countries should adhere, it does not directly implement laws or certification processes. The Federal Aviation Administration (FAA) is the NAA for the United States and plays a similar role, but the question specifically asks about the body governing certification requirements in a broader context, which is best represented by the National Aviation Authority concept. The Air Safety Board is typically involved in accident investigation rather than certification, making it less relevant in this context.