The Air Post Conferences


With the growing needs arising from the rapid development of international postal relations, the Universal Postal Union (UPU) was established on 9 October 1874 by the Treaty of Berne (which came into force on 1 July 1875) to promote the organization and improvement of world postal services in a spirit of international cooperation. The Universal Postal Union Congress is held every five years as the supreme authority of the UPU and brings together diplomats and postal operators from member countries.


Thanks to the First World War, aviation technology had considerably developed and aeroplanes were capable of flying long distances and of carrying substantial loads. The first airline companies were emerging and offered the possibility of carrying mail by air more swiftly than by terrestrial transport systems. The growing interest in the advancement of aviation encouraged postal authorities to reduce to some extent the transport by traditional means and shifted mail to the airways. As a result, it was discovered that airmail would regularly arrive at the destination on time and, even though the reduction of time was not too significant for the slow speed of the first airplanes, it easily beat out surface mail every time. Several air post conferences or congresses were held between the two wars with a significant economic and financial impact on aviation transport.


Air Mail Conference – The Hague – September 1927

At the Stockholm 8th Congress of UPU from 4 July to 28 August 1924, the possibility of using the airplane for the transportation of mail gained momentum and airmail transport was considered as an "extraordinary" ground service (as in 1920); but this time, the possibility of an air service serving many states was taken into account. The determination of the rates was left to the administrations using it (See Article 74 on “Airplane Services” in the Convention and Final Protocol of Convention signed at Stockholm on 28 August 1924). Although the agreement reached at the latter Congress had been in existence for only one year, a need for modification was recognized to consider unifying airmail surtaxes demanded of the public and to simplify the method of remunerating the air transport companies. As the signatory governments were bound by a five-year agreement during which time amendments to the convention were practically impossible to obtain and as the use of air transport had become sufficiently widespread, the Post Office of the USSR took the step in March 1927 of formally proposing a special Administrative Conference of UPU (Air Mail Conference on Postal Administration) for the consideration of the technical question of airmail provisions. Called at the suggestion from the Air Transport Committee of the International Chamber of Commerce (Chambre de Commerce Internationale, CCI) and the official initiative of the Postal Office of the USSR, this Conference met in the building of the Upper Chamber (Hall of Senate) at The Hague, Netherlands, from 1 to 10 September 1927, and was attended by thirty-eight postal administrations and fourteen air transport companies (although without a vote); the large participation indicated an awareness of the importance which airmail would have. In addition, one delegate from IATA and one from the International Chamber of Commerce were also present.


This Conference resulted in an agreement that established the airline companies as officially recognized carriers of mail; the basic rate to be applied in the settlement of the accounts for air transportation between administrations had been fixed at 6.5 centimes of gold francs for every indivisible fraction of 100 grams net weight and 100 kilometers. As a rule, this basic rate was limited to some European routes. The airline companies had requested 6 to 7.5 gold francs per ton kilometre on European daytime flights and a considerable higher charge for European night flights and intercontinental links. The Conference also initiated some significant rules and regulations concerning the acceptance and rapid delivery of airmail by the signatory powers, the expeditious handling of airmail by countries without air services, and the basis of accounting procedures for international airmail. The The Hague Conference of 1927 laid down the first airmail provisions, an event of historic importance in view of the fantastic development of those means of transportation in the international post. The Conference unquestionably marked the beginning of a new era for the airmail. See more information on this Conference by clicking on: 1927: Airline companies officially recognized as airmail carriers.


The UPU London Congress adopted in 1929 with minor changes the Air Mail Regulations that were established by this Conference. Later, more restricted meetings of countries directly concerned took place in Europe, with the participation of aeronautical authorities (see here below). The primary concern of these meetings was to take advantage of the speed provided by air transport for the benefit of the mail service between the principal cities.


As far as mail by air was to be concerned, the major developments of the following years were the European Air Mail conferences of Brussels in 1930, The Hague and Paris in 1937, and Brussels in 1938. These started by considering a European network; but thanks to developing technology and the fact that planes had become a normal method of transport for first-class mail within Europe, these conferences settled for establishing how the ordinary aviation services would be used.


European Air Mail Conference - Brussels – October 1930

The transport of mail by airplane having reached very large proportions in the United States of America, it was thought advisable to study the question from the European point of view. This success in the USA was chiefly due to the following causes:

1.  The transport was performed over great distances.

2. The airmails were very widely advertised.

3. The air traffic was performed night and day without interruption.

4. Regularity was insured by highly developed lighting equipment.

5. This lighting equipment included devices, which enabled pilots to fly in all weathers, and increased the security of the flights.

6. There was a uniform airmail fee.

7. There were so to say no formalities in the use of the airmails.

8. The transport of the mail was separate from that of passengers.


Europe could not offer less than America. The question of convening a European airmail conference in Brussels to bring about a rational organization of the airmail transport was examined and made possible by the Belgian Government. The European Air Mail Conference of Brussels (Conférence aéropostale européenne, held in the Palais des Académies) gathered together in 1930 representatives of twelve Postal Administrations and of seven Air Ministries of several European countries. The work of the Conference was divided into two entirely distinct parts. The first part, comprising the sittings of 13-15 October, interested exclusively the postal delegations of the twelve European countries (Germany, Belgium, Denmark, Finland, France, Great Britain, Italy, Norway, the Netherlands, Sweden, Switzerland and Czechoslovakia) and the UPU representatives attending the Conference. Its principal object was to examine the situation created by some European Postal Administrations which had, for some time past, been sending their mail (letters and postcards) by air, especially by night flights, for which they charged no special air fee and which bore no mark to show that the sender wished his correspondence to be sent by airplane.


The second part, with sittings from 16 to 18 October inclusive, was of a more mixed nature and consisted chiefly of an exchange of views between the postal and the aeronautic delegations, for the purpose of laying the foundation of a common programme and network to be studied more thoroughly in view of the Plenary International Conference (to be held in September 1931, in Brussels; in fact, this Conference was never held), at which all the European countries would be invited, for the organization and the improvement of air mail transport between the principal towns of Europe. Ten countries (Germany, Belgium, Finland, France, Great Britain, Italy, the Netherlands, Sweden, Switzerland and Czechoslovakia) and the UPU representatives attending the Conference were represented at this mixed Conference.


Preparatory Commission of the Air Mail Conference – Prague – June 1931

A Preparatory Commission of the future Air Mail Conference to be held in Brussels met in Prague, Czechoslovakia, from 8 to 18 June 1931, with representatives of the airlines, the Postal Administrations of 11 European countries: Germany, Belgium, Spain, France, the United Kingdom, Italy, the Netherlands, Sweden, Switzerland, Czechoslovakia, Union of the Socialist Soviet Republics and the Director of the International Office (Bureau International, a central point of contact at Berne functioning until 1947, between the UPU Congresses) of the UPU.


June 1931 – Prague

Special cancel - Air Mail Conference

The most complex question, submitted to the Commission, was the possible creation of a network of night services; above all, the concern was to know if one were to consider services functioning all the year or if, on the contrary, these services were to be limited to the summer months, at least initially. In order to gain the confidence of the public, the Commission unanimously decided that any night service considered would, at present, be limited to the summer months and be prolonged later on according to progress of the air technique.


The prior Conference held at Brussels had already discussed thoroughly the question of perception of an air surtax. The discussion had shown that certain countries were favourable to the principle of the sending of the surface mail by the way of the air without perception of the surtax, but also that the majority of Postal Administrations were not able to remove the air surtax already perceived. The Preparatory Commission confirmed the resolution of Brussels letting with each Administration the ability to maintain or remove the surtax with its liking, subject to the possible approval of the countries of transit. As for the adoption of a uniform surtax applicable to all the countries in Europe, the Commission solved to recommend the institution of a uniform and maximum surtax of 15-centime-gold per unit of weight, with the faculty to reduce the normally perceived surtax, in consultation with the bordering countries. The Commission unanimously decided to push back a request submitted by IATA for an increase of the transport price for the European network, that is to say a tariff of 10 or 12 centimes; this measure would harm the development of the airmail and the interests of the Companies.


The Commission carried out the examination of the possible creation of a specific postal air network. It concluded that the creation of such network could not be considered. The operating costs of the airlines were indeed very heavy, and, except in extraordinary cases, the income resulting from the transportation of airmail would not cover the costs. It was consequently necessary to consider the income coming from the transportation of passengers, freight, etc., and the subsidies granted by the Governments of the various countries. On the other hand, each European Postal Administration would provide an estimate (by country of destination) of the airmail to be carried by the various services and to plan with the Aeronautical Administration for the choice of the companies, which would be in charge of the subsidies.


The Preparatory Commission admitted the hope that by posing the first stakes of a rational organization of the air links of the European Post Offices, it would have been able to contribute to the development of the postal aviation. The plans for a European postal network were not followed, given the lack of uniformity in the findings at the Prague Preparatory Commission. Thus, the Conference, which would have been considered the recommendations of this Commission, could not take place. Policies based on competing and uncoordinated initiatives were hence put in place by the air postal companies and the national aviation authorities.


Pan American Postal Congress - Madrid – October/November 1931


3 October 1931 - Spain - Pan American Postal Union Congress

Held in Madrid, the Third Congress of the Pan American Postal Union started its work on 3 October 1931 and ended on 10 November. The 21 countries of the Pan-American Postal Union and Spain were present at this conference; Canada sent a delegate to this Congress. A new Convention declared the gratuity of territorial, fluvial and maritime transit, in the shortest period from 1 March 1932; other modifications brought ​​to the Postal Convention that governed American countries and Spain, ruled the weight of printed mail, the compensation for loss of registered mail, etc. At the same congress, the Pan American Postal Union was renamed Postal Union of the Americas and Spain, the latter country having joined the Union in 1924.


In 1921 at the First Pan American Postal Congress, the Pan American Postal Union was created in Buenos Aires, Argentina to form an international regulatory and unified postal service for the Americas (excluding Canada); at that time, the USA was not a member of the Universal Postal Union, but headed the Pan-American Postal Union. The Second Pan American Postal Congress was held in Mexico City in November 1926 and the Fourth Pan American Postal Congress was held in Panama in December 1936.


Postal Union Congresses – 1924, 1929, 1934 and 1939


10 May 1929 – United Kingdom –

9th UPU Congress

The Postal Union Congress is the main international meeting of the Universal Postal Union (UPU), used to discuss various issues affecting international postal services, such as legislation, the political climate, and other strategic issues. During the years of ICAN, the Postal Union Congresses were held as follows: 7th Congress: from 1 October to 30 November 1920, in Madrid, Spain; 8th Congress: from 4 July to 28 August 1924 in Stockholm, Sweden; 9th Congress: from 10 May to 28 June 1929 in London, UK; 10th Congress: from 1 February to 20 March 1934 in Cairo, Egypt; 11th Congress: from 1 April to 23 May 1939 in Buenos Aires, Argentina.



11 December 1939

Bird carrying record

The postage paid franking and the first airmail regulations (outcome of the Administrative Conference held in The Hague in 1927) were approved at the 9th Congress held in 1929. The 1934 Congress changed regulations as regards the provisions concerning the transport of letters by airmail and concerning the conveyance of postal parcels by air.


The 11th UPU Congress was held from 1 April to 23 May 1939 in Buenos Aires, Argentina. At this Congress, the service of Fonopost or Phonopost, an experimental postal service in Argentina to record a person's voice and deliver the resulting recording by mail, was demonstrated; the recordings used 8 inch 78 rpm acetate gramophone records. In December of the same year, the Argentine Post Office issued three stamps to mail such records. This service was approved by the UPU; however, it was later removed in 1969 at the Tokyo UPU Congress.


European Air Mail Conference – Brussels – June 1938

The European Air Mail Conference (Conférence aéropostale européenne) was held in Brussels from 16 to 25 June 1938 (in the Salle des Glaces of the Egmont Palace) at the request of the Belgian Postal Administration.  Twenty-six postal administrations took part in this conference. The aeronautical services of seven European countries as well as the International Commission for Air Navigation (ICAN) were also represented. This Conference agreed on the harmonization of provisions to aid the expeditious handling of airmail and the related accounting procedures. It is a follow-up of the The Hague Conference of 1927. The Conference held nine plenary sittings. Two Committees were formed, one to prepare the scheme of an Agreement for the transport of non-surcharged airmail in Europe, the other to prepare the airmail forms (bills of lading and bills of delivery).


Belgium - European Air Mail Conference – Postmark: 23 June 1938

Limited conferences convened in The Hague, Netherlands, in April 1937 and in Paris, France, in June 1937 had expressed various needs, all tending to have the aeroplane regarded as normal means of transport for letters and postcards and been used as well as the other means of transport, without the perception of any surtax, every time that, by this means, the distribution of these correspondences could be advantageously accelerated. At that time, the aeroplane was regarded as a normal means of transport.


Moreover, the desire had been expressed that the transport cost of mail by air be reduced by at least 50% taking it for granted that the air navigation companies would on their part consent to at least an equivalent reduction. Considering the requests pointed out here above, the International Air Transport Association (IATA), by a decision dated 18 January 1938, had consented to lower the transport rates from 6 francs to 2.50 gold francs per metric ton kilometre (on European routes) for the routing of the mail without surtax. This rate would be applied for a three-year experimental period, at the expiration of which the IATA might be disposed to consider a further reduction and bring the rate down to 2 francs.


Since a certain number of countries in Europe had already started sending non-surtaxed mails, it appeared that the moment was opportune to consider the generalization of this means of transport.


The Conference had considered that it was advisable to take new steps at the IATA in order to obtain from airline companies a reduction of the tariff to 2 francs as soon as possible. The conference had also approved the development of a regulation having the aim of fixing the conditions under which air transport of the non-surtaxed mail could be carried out, i.e., methods of accounting between the postal administrations, as well as the commitment by the postal administrations which use air communications for the transport for their non-surtaxed mail to convey by the same means the mail which was carried for other countries, while limiting this obligation to the letters, postcards, money orders and values to be recovered. Lastly, the Conference had suggested that it was not necessary to draw the attention to the non-surtaxed mail by a label Par Avion/By Airmail and that the provisions of Universal Postal Convention would be applicable in all that was not expressly regulated by the provisions of this Conference on the air transport of non-surtaxed mail.


On 15 March 1938, the Belgian Post Office issued a set of 5 stamps (depicting King Léopold III, Aviator) for the 10th anniversary of the National Commission on Aeronautical Propaganda (Comité national de propagande aéronautique). The National Commission on Aeronautical Propaganda was founded in the late 1920s with the support of the Ministries of Communications (from which depended Aviation) and National Education to disseminate aviation information and familiarize as much as possible young people with aviation matters. This Commission issued several philatelic items with the above-mentioned five stamps to commemorate the European Air Mail Conference.


European Post Congress – Vienna – October 1942

A Congress of the European Postal and Telecommunications Union met in the Reich General Post Office of Vienna on 12 October 1942, in presence of representatives of the Postal and Telecommunications Administrations of thirteen European countries. The delegates decided to organize a European collaboration in the domain of the Post and Telecommunications on the lines of the Universal Postal Convention and the International Telecommunication Convention.



UPU Congress of 1924 held in Stockholm.

The second cover bears the special hand-stamp of the last day (28 August) of the Congress.


Official Delegate mailing label used at the 9th Universal Postal Congress held in London in 1929. The label printed with the delegate’s name (Dr. R. Furrer was from Switzerland) and hotel address is 108x70 mm. There is no franking.

Violet cancel linked to the Post Union Congress. Violet congress cachet with the British Crown. Red London W1 postmark.



13 to 18 October 1930 - Brussels – European Air Mail Conference 


8 to 18 June 1931 - Prague – Preparatory Commission of the Air Mail Conference

Registered mail.


8 to 18 June 1931 - Prague – Preparatory Commission of the Air Mail Conference

Postcard with a view over Charles Bridge and the Old Town Bridge Tower.



First International Aviation Exhibition held in Belgrade, Yugoslavia

from 28 May to 13 June 1938. Circular Date Stamp: 11 June 1938.

Event cover sent to the Yugoslavian Delegate to the European Air Mail Conference held at the Egmont Palace in Brussels from 16 to 25 June 1938. The back of this cover shows the postmark of the conference dated 17 June 1938. The vertical text in French at the left-side reads as follows: Exposition internationale de la navigation aérienne, which in fact should have been (when translated from the German text): Exposition aérienne internationale.


16 to 25 June 1938 - Brussels – European Air Mail Conference



Belgium - Postcard (recto and verso) with a stamp issued on 23 March 1938 for the European Air Mail Conference (June 1938) on behalf of the National Commission on Aeronautical Propaganda, showing King Léopold III, Aviator, standing in front of the Fairey Fox AF-6078 aircraft. The Fairey Fox formed the backbone of the Belgian Air Force in the 30s and was even built under licence in Belgium.


Official First Day of Issue sheet (dated 16 June 1938) prepared by the National Commission on Aeronautical Propaganda to commemorate the opening of the European Air Mail Conference at Brussels. The sheet shows the 5 stamps with King Léopold III, Aviator.


Souvenir sheet issued by the National Commission on Aeronautical Propaganda on the occasion of the Second International Philatelic Fair held in Ostende, Belgium on 13 August 1938.

The sheet shows the 5 stamps with King Léopold III, Aviator.


Commemorative First Day Card issued for the European Postal Congress at Vienna.

12 October 1942 - The stamps depict a postilion in various poses.