Home2001 Treaties and Agreements ...Multilateral (13148) – Agreement on the Liberalization of International Air Transportation hide Multilateral (13148) – Agreement on the Liberalization of International Air Transportation TIAS Office of Treaty Affairs December 21, 2001 Transportation: Liberalization of International Air Transportation Agreement done at Washington May 1, 2001; Entered into force December 21, 2001. With annex and appendix. Download Attachment [997 KB] Tags Aviation and Maritime Transportation International Law, Treaties, and Agreements Multilateral Relations and Cooperation