World War I broke out in 1914 and Kármán was called up for military service in the Austro-Hungarian army, and as part of his war work he worked on the design of military aircraft and an improved design for a helicopter.
World War I Nasira out sa 1914 at Kármán ay tinatawag na up para sa mga serbisyo sa militar ang Austro-Hungarian hukbo, at bilang bahagi ng kanyang digmaan trabaho siya nagtrabaho sa disenyo ng militar ng sasakyang panghimpapawid at isang pinabuting disenyo para sa isang helikoptero.