ICRC databases on international humanitarian law
Treaties, States Parties and Commentaries
Treaties and Documents
Geneva Conventions of 1949 and Additional Protocols, and their Commentaries
Historical Treaties and Documents
Rules concerning the Control of Wireless Telegraphy in Time of War and Air Warfare. Drafted by a Commission of Jurists at the Hague, December 1922 - February 1923.
Part II: Rules of Air Warfare#Chapter I: Domain of application: classification and marks. - Art. 9.
Art. 9. A belligerent non-military aircraft, whether public or private, may be transformed into a military aircraft provided that such transformation be made within the jurisdiction of the belligerent State to which the aircraft belongs, and not on the high seas.