Williams borrows, Horner borrows, they all borrow.
"Concerning Hobbits" and the hymn "This is My Father's World" start almost exactly the same...
John Williams "borrows" all the time as well.
If you listen to classical music you notice these things all the time.
Aliens soundtrack, alot was ripped off from Holst: The Planets, especially Mars, Bringer of war. The planets has to be one of the most copied templates for sci fi fantasy movies ever. Has awesome spacey elements to it.
Of course, but I'm surprised by the extent of the un-deviation in the LOTR phrase. There is a ton of Holst's and Stravinsky's textures and flavours in Star Wars but never an entire - and highly prominent - melody line lifted verbatim and presented as a main figure.
One great example of this is the Death Star run in A New Hope. Just before it explodes, it sounds just like the end of Mars Bringer of War.
Compare 6:56 -
Gustav Holst - The Planets - Mars, the Bringer of War - YouTube
Star Wars Episode IV Soundtrack - The Battle of Yavin - YouTube