Zeppelins carried a great deal of mail, mostly because zeppelin first flight covers and other philatelic covers were prized by stamp collectors and the postal revenue from these items financed much of the cost of operating the zeppelins.
Zeppelins were the fastest way to send mail across the ocean in their day, and so some commercial mail also exists, especially on the South Atlantic route. LZ-127’s service to South America cut mail time from weeks to days and was especially popular among businessmen.
Hindenburg’s 2-1/2 day service was the fastest way to send mail between Europe and North America in 1936, when ocean liners took five days or more to cross the Atlantic. Hindenburg’s irregular schedule made the service unappealing for most business uses, but no faster way to send mail existed until May, 1939, when Pan American Airways inaugurated airmail service across the North Atlantic in Boeing 314 Clipper flying boats.
Zeppelins did have mail competition across the South Atlantic beginning in 1934, when the German airline Deutsche Luft Hansa began a multi-leg airmail service between Europe and South America which crossed the Atlantic at its narrowest point, between Gambia in Africa and Natal in Brazil, offering a coordinated mail service between zeppelins and airplanes.