Obviously I'm a film fan and I have been all my life. I was born in 1979 so my first impressions of film are of the 1980s which was a very important decade for film scores. John Williams' scores for Star Wars and Indiana Jones radically changed the game, dazzling everyone with the concept of using full orchestra and Wagnerian themes even for a space movie. Almost all film scores sounded different afterwards--even Williams himself had had a relatively unremarkable career for decades before Star Wars, he effectively became another kind of composer after Star Wars and so did a lot of other composers. Williams couldn't score every movie so you had a number of other composers tasked with fitting this new mould--Alan Silvestri, Jerry Goldsmith, and a few others distinguished themselves particularly well but maybe the best at adapting to this new era was James Horner.
Horner's themes for Star Trek II fully eclipsed those written by Jerry Goldsmith for the first film to be most popularly associated with the original series crew in films. Goldsmith's score wasn't bad and came to be associated with Star Trek The Next Generation and a lot of the stronger association people have with Horner's score with Kirk's crew is probably related to the fact that Star Trek II is simply a better film. But certainly what Horner accomplished is part of that, managing to capture an awe of boundless ether and an echo of seagoing adventure to fit with Nicholas Meyer's vision of the film as Horatio Hornblower in space. It bears the marks of homage to Erich Wolfgang Korngold's score to the 1940 film The Sea Hawk but mostly it's unmistakeably Horner. A comparable score was one of the most noticeable absences in J.J. Abrams' remake.
Horner reworked some of his Star Trek score when he was called in late into production to score James Cameron's Aliens in 1986, once again a sequel to a film that had been scored by Jerry Goldsmith.
Like Goldsmith before him, Horner quotes the worried strings from Gayene, a ballet by Aram Khachaturian which was used for exterior spaceship shots in Kubrick's 2001, and uses them for lonely visions of vessels drifting through cold vastness. But Horner's score is best remembered for the percussion, tight military drums foiled by alarming cymbals and elephantine brass. Cues from the film were used in movie trailers long afterwards and it's no surprise that Cameron would choose to work with Horner time and time again, including for his last two enormously successful films, Titanic and Avatar. It's for Titanic in particular that Horner is widely recognised, its score's Celtic quality bearing a strong resemblance to a film Horner had worked on previously, Braveheart.
But to trace the recurring motifs of Horner's work back further, it's been said that his work of the late 90s and early 2000s mostly began with his most Wagnerian score from the most Wagnerian era of film scores.
Willow as a film may not have aged terribly well but I really want it to work mostly because of Horner's soundtrack. I'm still hoping to find the right level of intoxication to make it work for me one night but I need no amount of alcohol to enjoy Horner's score. So the man's gone now but he left us with quite a lot. Well, assuming he really is gone, I hope this story gets straightened out.