For the past forty years, Igor Pasternak has pursued a lighter-than-air vision: to build gigantic airships that haul cargo to otherwise inaccessible parts of the planet. In high school, in Ukraine, Pasternak formed an airship club; at Lviv National University, where he studied civil engineering, he established an airship-design bureau. Eventually, he settled in southern California and started Aeros, which builds blimps for surveillance and other purposes. His prototype cargo airship, the two-hundred-and-sixty-foot-long Dragon Dream, was destroyed in 2013 when its hangar collapsed on it. Unfazed, Pasternak now aims to produce a fleet of “Aeroscraft” cargo airships, the largest of which will be more than nine hundred feet long and able to carry five hundred tons.  Pasternak spoke recently with the director and producer Gabe Polsky. Polsky’s documentary, “Red Army,” played at the 2014 Cannes, Telluride, Toronto, and New York Film Festivals, and was released in theatres in 2015.