Great idea for a thread. I wish I had more suggestions. I'm having a hard time thinking of movies that remind me of The Silver Chair specifically. I agree that Laputa: Castle in the Sky has a very Narnia-esque feel to it. If I remember correctly, a few of the other movies made by the same studio do too.

The only Silver Chair-esque movie that comes to my mind (there are probably much better ones I can't think of) is Inside Out. It's not tonally like The Silver Chair at all. But the character of Sadness has a very similar role to Puddleglum. Initially, the main character dislikes having her for a companion just like Jill Eustace do Puddleglum, because she's always being negative. But as the story goes on, she comes to see that Sadness' advice is good and by the end, she is crowned the hero of the story.

I wouldn't say Puddleglum's personality is much like Sadness' though. He's more like a combination of Joy and Sadness. He always expects the worst but he's always optimistic about it.

OK, this is probably not just a coincidence, considering Lewis' reading tastes, but-

There's Macbeth, (yes, there's a movie version) in which a murderous king is foiled by an army of moving trees (OK, maybe they're not actually trees, but... close. And if they're soldiers using tree camouflage, then you could say they look like incredibly "leafy and branchy people".... so that works.) There's also some black magic involved; only in this case it actually gets used. And works.
Then there's Hamlet, (yes, there's a movie version of this too),all about an orphan prince fighting his usurping, fratricidal uncle... only no Talking Animals get involved. (Unless we're talking about the updated version of Hamlet, where they do it with lions. Animated lions. ) It also resolves with single combat; only the prince himself does the fighting, not a High King from Denmark's Golden Age.

Sounds like William Shakespeare should get a little credit for Prince Caspian.

Sounds like William Shakespeare should get a little credit for Prince Caspian.

Perhaps he should - the moving trees could indeed look like some sort of inspiration.

Shakespeare gets a little credit in Silver Chair, though. When the children meet the enchanted prince in the underground city, it's stated quite clearly (only the author isn't mentioned).

A young man with fair hair rose to greet them. He was handsome and looked both bold and kind, though there was something about his face that didn't seem quite right. He was dressed in black and altogether looked a little bit like Hamlet.

No, Aslan is NOT Anthony Hopkins in ‘The Silence of the Lambs’!

I find this really funny, because Anthony Hopkins did play C. S. Lewis in Shadowlands.

Then there's Hamlet, (yes, there's a movie version of this too),all about an orphan prince fighting his usurping, fratricidal uncle... only no Talking Animals get involved...It also resolves with single combat; only the prince himself does the fighting, not a High King from Denmark's Golden Age.
Sounds like William Shakespeare should get a little credit for Prince Caspian.

Back when PC was in pre-production, we had a thread about possible code names for it. (It ended up as Toastie) I think it was I who suggested Hamlet.