This is amazing! The details on the pages witht the sketches on, the little image in the bottom right, the girl's hair and face. And the sense of motion in the flow of ink from the pen is so natural. The little boy with the winged cat are just so adorable as well! I love the texturing on the cat's fur and wings.
The drawing is lovely, but there is something awkward about it...
I believe it's the orange in the background: it's only in one area of the piece and nowhere else so all of my attention goes straight there. The ink from the pen tries to move you eye around the piece but the orange is stronger. So instead of looking at the lovely intricate castle, I look at the orange.
I do love that the flying papers go in the opposite direction of the the swirling ink, making you look at the girl, but then the papers fly straight into the orange, so again my eyes linger there.
I noticed that you tried to make a transition between the penciled castle and airship to the boy by making the boy's pants also penciled, but in my opinion it doesn't work very well in that I think it needs to be exaggerated more, maybe also trying that same technique with the cat.
Actually the transition between all the different styles of drawing is very curt, not very blended.
This is just my opinion, but I would try adding some of the orange elsewhere in the drawing in order to tie in the one blotch of it, maybe in the corner behind the girl and making smoother transitions between art styles. You have great movement throughout the piece, but if you don't pay attention to the movement of your colors and techniques, the foreground movement will only accomplish so much.
I say all of this because as much as I love it when people compliment me on my work, most of the time I would rather them tear it apart and give me actual criticism.
I do love the piece, and your art style is gorgeous. Keep drawing.