The growth of ICAO


On 6 June 1945, the required 26 States, including each of the 20 States elected to the Council, had accepted the Interim Agreement on International Civil Aviation. Thus, as per Article 1 - Section 1 of the latter Agreement, the Provisional Organization (PICAO) was born, within six months after the closing of the Chicago Convention.


On 5 March 1947, Spain was the 26th state to deposit, with the Government of the USA, its instrument of ratification to the Chicago Convention. Consequently, this Convention came into force on 4 April 1947 (i.e. 30 days later), among the states having thus ratified.


ICAO’s success is evidenced by the dynamic and sustained increases in the number of States adhering to its Convention on International Civil Aviation. The following table shows a summary of progress in terms of submitted instruments of ratification of this Convention.


However, two factors contributed largely to ICAO’s growth in terms of Member States:

  1. The emancipation in Africa, especially between 1960 and 1962. New countries were created by the decolonization; in a few years, 23 new States joined ICAO; and
  2. The breakup of the Socialist Federal Republic of Yugoslavia (in the 1990s) and the dissolution of the Soviet Union (starting from December 1991) led to the emergence of new States, which joined ICAO.


South Sudan became an independent state on 9 July 2011 and became the 191st member of ICAO on 10 November 2011, 30 days after South Sudan’s notification of adherence was received, on 11 October 2011.


In 1945, the air transport industry carried nine million passengers to the limited destinations available to it at that time. As of 2014, that number has grown to more than 3.3 billion passengers travelling on scheduled commercial international and domestic operations across a very extensive global network (up from 3.1B in 2013). These are astounding statistics and ICAO has proudly contributed to them with the development of a unified global community which now provides reliable and affordable air travel to citizens and business everywhere in the world.



Number of Contracting States
May 1946 8
March 1947 26
1949 56
1954 65
1957 70
1960 80
1962 93
1964 107
1967 116
1971 120
1975 132
1978 143
1982 150
1994 182
2008 190
2011 191


Several countries issued stamps to commemorate their admission to ICAO.


Republic of Korea - 11 December 1962

10th Anniversary of Korean admission to ICAO

First correct appearance of the ICAO first official emblem (adopted by the 10thSession of the Assembly, held in Caracas in June-July 1956).


Republic of Korea - 11 December 1977

25th Anniversary of Korean admission to ICAO


Brunei - 30 April 1986

Admission to International Organizations:

WMO (26 December 1984)

ITU (19 November 1984)

UPU (15 January 1985)

ICAO (3 January 1985)

The four stamps are attached to opposite sides of a piece of gutter paper that depicts the National flag of Brunei.


Albania - 19 October 1990 - Admission to ICAO

The cover shows Albania’s national flag, the world map, a French Aérospatiale Sud-Est SE 210 Caravelle aircraft, and a runway of flags of countries having main air corridors/routes linking Albania with the rest of the word.




Democratic People’s Republic of Korea - 14 September 1997

20th Anniversary of admission to ICAO

Three sheet-lets of two stamps and a central label.


Republic of KOREA – 11 December 2002

50th Anniversary of admission to ICAO – Multicolored aircraft trails