Williams' Inspiration
John Williams has done so many different flavors of scores for so many different flavors of films at this point that you could probably cast a Classical inspiration net very wide indeed!
In the case of Star Wars, I would say Richard Wagner is a good bet. I vaguely remember George Lucas saying that he had used some Wagner clips to indicate to JW the sort of "operatic" experience he was trying to create for audiences. Certainly the JW soundtrack was "Wagnerian"-powerful: at least as important to the movie as the on-screen visuals.
Raiders was, I think, the same approach. You were meant to be "very aware" of the music, not just let it be a background-enhancement. In Jaws, on the other hand, the music was not supposed to distract you from the action, just accent it.
Strangely, just as the second and third Star Wars and IJ movies don't seem to me to recapture anywhere near the thrill of the first film, the follow-up JW soundtracks also strike me as just assorted extra music using pieces of the initial soundtrack themes. Just about everything on the Star Wars and Raiders album is world-class, and just about everything on TESB, ROTJ, TOD, and LC is forgettable.
Michael Aquino