Before he was famous for being a reclusive germaphobe -- or, in screenwriter John Logan's words, ''the old man in Las Vegas with long fingernails and shoe boxes on his feet watching 'Ice Station Zebra' as his Mormon aides put codeine in his arms'' -- Howard Hughes was famous for being a few other things: movie mogul, Hollywood lady-killer, and above all, pioneering aviator. Martin Scorsese's reported $100 million epic, starring Leonardo DiCaprio as the eccentric entrepreneur, focuses on the 20-year period when America's first billionaire revolutionized the business of air travel. ''The film presents a Howard Hughes not really known,'' says Scorsese, who was recruited to the project by his ''Gangs of New York'' star DiCaprio. The actor developed the film with Logan and helmer Michael Mann, but the latter begged off due to biopic burnout after ''The Insider'' and ''Ali.'' Scorsese came aboard despite a fear of flying. ''But the more anything upsets me,'' he says, ''the more I want to learn about it.''
''The Aviator'' does deal with the Hollywood Hughes, too. Scorsese, noted for his encyclopedic knowledge of movies, says he got some cineast kicks out of restaging scenes from ''Hell's Angels,'' one of the two films Hughes is credited with directing. The film also chronicles romances with Katharine Hepburn (Cate Blanchett), who the film argues was the love of his life, and Ava Gardner (Kate Beckinsale), with whom, the film suggests, Hughes was sexually obsessed. ''He was attracted to large-breasted women, and she had the biggest pair around,'' says Beckinsale. Meanwhile, Logan and Scorsese both say they went to great lengths to present sensitively and seriously the mental illness that would ultimately define Hughes' image -- his terror-stricken interface with the world. ''Like washing his hands. How he deals with a doorknob. How his people bring him lunch,'' says Scorsese. ''The details entrench him in a kind of madness that he can't move out of.''
Since wrapping last November, Scorsese has been working to whittle the film to about two hours and 40 minutes. Miramax and Warner Bros. will jointly distribute ''The Aviator,'' and producer Graham King says all is well between Scorsese and Miramax's Harvey Weinstein, who publicly clashed over the running time of ''Gangs.'' ''The difference is night and day,'' says King, who adds that no one in the ''Aviator'' camp dares utter the O-word. ''But wouldn't it be great if this could be the one for Marty?''
WHAT'S AT STAKE That elusive O -- as in Oscar, which Scorsese has never won.