the route to be followed in its territory by an international air service and the airports that such a service may use; impose or permit such a service to pay fair and proportionate charges for the use of such airports and other facilities; Such charges shall not be higher than they would be paid for the use of such airports and installations by their national aircraft providing similar international services: provided that the charges levied for the use of airports and other facilities are subject to verification by the Council of the International Civil Aviation Organisation established under that Convention; To report therein and make recommendations for the consideration of the State or States concerned. .