In 1988, the first considerations into the technological and economic feasibility of reviving the Zeppelin industry began; this included examinations of historic Zeppelin documentation as well as current designs for airships. In December 1990, a feasibility study and accompanying market research program found an initial sales potential for around 80 Zeppelin airships for purposes such as tourism, advertising, and scientific research. In mid 1991, the newly formed development team filed several patents on various technologies that would be later used on the subsequent airship, these included propeller arrangements, structure and girder design, and ballonet implementation. In March 1991, a flyable remote control proof of concept model was demonstrated, which is claimed to have revealed excellent flight characteristics from the onset.