The International Civil Aviation Organization (ICAO) classifies its member countries into specific categories. First, we have the Contracting States. These are countries that have ratified or agreed to the Chicago Convention, following its Chapter XXI. As of August 2020, there are 193 such states. On the other hand, non-Contracting States are those that have not ratified the Chicago Convention but are still members of the United Nations or its specialized agencies. The only two non-Contracting States are the Holy See and Liechtenstein. Additionally, there are countries that neither signed the Chicago Convention nor belong to the UN or its agencies.
When it comes to air navigation services, states fall into two main groups: Providers and Users. Provider countries are those located within a specific region or possess territory in that area. They are responsible for offering essential services and facilities needed in the region. Conversely, User countries are not situated in the region but have air carriers registered that operate international flights within it. Interestingly, a single state can be classified as both a ‘provider’ and a ‘user,’ depending on its geographical location and territories.
