I'm looking for the name of a kids movie, but i can only remember the gist of it!

I'm looking for the name of a kids movie, but i can only remember the gist of it a few details.?

heres what I know-
its an animation, it starts with a boy and his dad at a parade, the
boys bed flies and takes him some where else where theres a princess and a king, he has a pet flying squirrel and the king has a train set, theres a trickster guy who convinces him to open this door with this key, and this black stuff like kidnaps the king.....or something. please help, I need the name!!!

Little Nemo: Adventures in Slumberland

A young boy whose dreams transcend reality is sucked into his his own fantasy, which is everything he has dreamed of until he unleashes a century old secret that may not only destroy this perfect dream world but reality itself.