The treaty rights behind an international flight
An airline cannot assume it may fly a route just because it has aircraft, customers, and landing permission. Governments negotiate air-service agreements that grant airlines from each country permission to operate particular international services. The third and fourth freedoms are two of the basic rights such agreements can provide: they govern the traffic an airline may carry between its home country and another country.
That permission is about commercial traffic, not simply crossing a border. A plane might be allowed to land abroad for technical reasons without being allowed to sell tickets there. The freedoms matter because they let an airline offer a scheduled service to customers, subject to the terms the governments have agreed.
Why the direction matters
Imagine an airline based in Country A operating between A and Country B. The rights determine whether it can sell seats to travelers going from A to B, from B to A, or both. They do not, by themselves, let that airline carry passengers between two places in Country B, or continue from B to a third country with local passengers. Those are different traffic rights and require separate permission.
In practice, governments may specify which airlines can use the rights and what routes or services are covered. So the freedoms are not a universal license for every carrier to fly anywhere. They are the legal building blocks that make many ordinary international routes possible—and help explain why an airline’s ability to serve a destination can depend on negotiations between governments, not just demand from travelers.
