Where are the minimum requirements for commercial air traffic between countries defined?

The minimum requirements for commercial air traffic between countries are defined by the International Civil Aviation Organization (ICAO). ICAO is a specialized agency of the United Nations that establishes global standards and regulations necessary for the safety, security, efficiency, and regularity of international air transport. Its regulations are essential for harmonizing aviation policies among member states and ensuring that international air traffic operates under consistent standards.

By defining these regulations, ICAO enables countries to manage their air traffic systems effectively while fostering cooperation and safety in international aviation. These standards include guidelines on airworthiness, flight operations, and air traffic management, allowing for a smoother and safer experience for passengers and cargo.

While other options, such as national laws or aviation codes, might govern domestic aviation operations or specific national regulations, they do not provide the international framework that ICAO's regulations do. JAA (Joint Aviation Authorities) primarily dealt with European aviation standards before it was integrated into the European Union Aviation Safety Agency (EASA). National laws are specific to individual countries and cannot establish minimum requirements for commercial air traffic on an international scale. Thus, ICAO regulation is the most suitable and comprehensive source for defining minimum air traffic requirements between countries.