"They wouldn't let us bring it based solely on the fact that it was a Hummer," Bob Goldstein, Cyclone vice president for finance and marketing, told The Robb Report.
The Hummer is powered by a mixture of hydrogen and gasoline that, according to Cyclone, reduces C02 emissions by 65 percent overall. In city driving, the Hummer uses hydrogen as the primary fuel supply when the engine is idling.
The company also produces a hydrogen-only system that is currently operating in a Chevrolet SSR.
Source: The Robb Report