The actor who's been king of the world is now sitting on top of an airplane, and partly because of DiCaprio's young age (he just turned 30), the movie, called "The Aviator," (search) focuses on Hughes' earlier days in Hollywood and in aviation.
"We specifically chose to concentrate on the younger part of [his] life, before the onset of these obsessions and madness. It's why the movie got made," DiCaprio told FOX News at "The Aviator" premiere Tuesday night.
Opening Friday, "The Aviator" has been highly anticipated for years. At different points, actors including Warren Beatty and directors like Michael Mann have wanted to tell the story of the filmmaker/aviation enthusiast who dated a bevy of beauties before succumbing to obsessive compulsive disorder.
Even for legendary filmmaker Scorsese, "The Aviator" was a monumental undertaking. It involved a lot of computer-generated imagery, but at heart it's about a man. That's what drew the director to the material.
"The film is something I wanted to do for a long time ... an epic which has [a] deep personal story to it," Scorsese told FOX News.
"We put a lot of time into the project, [a] phenomenal amount of time," DiCaprio added.
"The Aviator" focuses on Hughes' scrappy years from the late 1920s to the late 1940s, when he fought the Hollywood establishment and pushed boundaries on sex and violence in film, dated parades of starlets and oversaw creation of the world's biggest and fastest planes.
Cate Blanchett (search) co-stars as Katharine Hepburn, whom Hughes dated for three years. Kate Beckinsale plays Ava Gardner, another of Hughes' longtime companions. Gwen Stefani (search) has one line as Jean Harlow.
Critical consensus for "The Aviator" is slightly mixed to positive, with some feeling it could win best picture when the Oscars roll around.
Associated Press film critic Christy Lemire commended the film for its "astounding," "dazzling" and "thrilling" visuals, attention to detail and strong performances, but wished she would have left knowing more about Hughes.
"It's a spectacle. And similar to Scorsese's last collaboration with DiCaprio, the 2002 behemoth 'Gangs of New York,' it's ultimately superficial and not completely satisfying," she wrote.
The film, DiCaprio and Scorsese are all nominated for Golden Globe awards, something DiCaprio says is nice, but not of paramount importance.
"It's not the reason why you do movies ... but to have people say look we are going to single a movie out and give it a lot of nominations is a great feeling, a rewarding feeling," he said.
FOX News' Bill McCuddy and The Associated Press' David Germain contributed to this report.