Artikel 4

1. Each Contracting Party shall have the right by written notification through diplomatic channels to the other Contracting Party to designate an airline to operate air services on the routes specified in the Annex and to substitute another airline for an airline previously designated.
2. On receipt of such notification, each Contracting Party shall, without delay, grant to the airline so designated by the other Contracting Party the appropriate operating authorizations subject to the provisions of this Article.
3. Upon receipt of the operating authorization of paragraph 2 of this Article the designated airline may at any time begin to operate the agreed services, in part or in whole, provided that it complies with the provisions of this Agreement and that tariffs for such services have been established in accordance with the provisions of Article 6 of this Agreement.
4. Each Contracting Party shall have the right to refuse to grant the operating authorization referred to in paragraph 2 of this Article, or to grant this authorization under conditions that may be deemed necessary for the exercise by the designated airline of the rights specified in Article 2 of this Agreement, if it is not satisfied that substantial ownership and effective control of the airline are vested in the Contracting Party designating it or in its nationals or in both.