On 5th December 1919, the Sociedad Colombo-Alemada de Transportes Aeros (SCADTA), also known as the Colombian-German Air Transport Society, was granted a contract to carry airmail in Colombia. The contract with the Colombian government not only gave SCADTA the legal right to carry airmail in Colombia, it gave SCADTA the right to issue its own airmail stamps (to prepay SCADTA airmail fees in Colombia).
The SCADTA Centavo stamps of the third, fourth and fifth issue (1921-1929) are showing the Magdalena River with the volcano Nevado de Tolima in the background.
The SCADTA Peso stamps of the third and fourth issue (1921-1928) are showing the main square of the city of Bogota with the Cerros Monserrate and Guadalupe in the background.
SCADTA Airmail stamps of the third and fourth issue were overprinted for sale in some countries outside Colombia. The agencies sold SCADTA stamps overprinted with large letter, the initials of the country of origin in Spanish. The issues were overprinted to prevent currency speculation.
The complete of the overprinted letters are: A=Germany, Austria and Czechoslovakia, A-U=Argentina-Uruquay, B=Belgium, Bo=Bolivia, Br=Brazil, C=Cuba, Ca=Canada, Ch=Chile, CR=Costa Rica, D=Denmark, E=Spain, EU=United States, F=France, G.B.=Great Britain, H=Netherlands or Netherlands Antilles, I=Italy, P=Panama and Canal Zone, Pe=Peru, S=Switzerland and Liechtenstein, Su=Sweden, V=Venezuela.
All countries had the exact same values but some countries used up to three different overprint types. And some of these same values were also overprinted in different colors. Collectors searched out a total of 697 different stamps!