I believe that Sam Elliot plays the cowboy/narrator at the end of The Big Lebowski - a gravel voiced wisdom-ownin’ character. And I think that the pilot who sits down next to Ryan Bingham in Up In The Air is a gravel voiced wisdom-ownin’ character played by Sam Elliot? Am I right?
Haven’t seen the Clooney film yet, but Elliot is listed in the IMDB for UitA.
Sam Elliot is in a lot of movies.
It looks like another Coen Brothers’ film is drawing more specific comparisons with the Reitman one (some spoilers, so beware).