https://www.icao.int/sites/default/files/postalhistory/aviation_history_the_catapult_mail.htm https://www.icao.int/sites/default/files/postalhistory/aviat... C

https://www.icao.int/sites/default/files/postalhistory/aviation_history_the_catapult_mail.htm https://www.icao.int/sites/default/files/postalhistory/aviat... Catapult mail service In the years immediately preceding Hindenburg (1928-1935), state of the art mail delivery service catapulted airplanes with mail while the ocean liner was still on sea. Hindenburg made that unnecessary.