I'm looking for a story that I heard on audiobook about 10 years ago. It was about a guy (young adult maybe?) who finds out that he can walk between planes. There are a whole arc of worlds, that range from pure science to pure magic. He is from one in the middle.
He finds that there is a version of him on every Earth, and they are the only one who can walk between the worlds. I believe there is a scene on a flat area with a red balloon. The antagonist has a large fleet of ships.
I want to say it's called Planewalker but that didn't show anything except for Magic the Gathering books (even using the