In an Eastern philosophy "horses" are symbolic/representative of the 5 senses - the things that keep us tied to the physical/material plane of existence. When you can transcend the limitations of these senses and achieve a higher level of consciousness, you are leaving the "horses" behind - "flying over them.".

You told me, I've seen it rise
But it always falls
I've see [bad word]  I've seen him go
He said, "All things pass into the night"
And I said, "Oh no sir, 
I must say you're wrong 
I must disagree, oh no sir,
I must say you're wrong
Won't you listen to me?"

You told me, "I've seen it all before
I've been there, 
I've seen my hopes and dreams 
A-lying on the ground
I've seen the sky just begin to fall"
He said, "All things pass into the night"
And I said, "Oh no sir,
I must say you're wrong
I must disagree, oh no sir,
I must say you're wrong
Won't you listen to me?"

Goodbye horses, I'm flying over you
Goodbye horses, I'm flying over you
Goodbye horses, I'm flying over you
Goodbye horses,
I'm flying, flying, flying over you