"Up" Symbol (with spoiler)

One symbol I figured out on the way out of the theater after seeing "Up" was the house attached to the main character, Carl.

When Carl and Russell first land in Paradise Falls, they are not at the correct site, so Carl decides to literally pull the house to where he wants it. However, the longer the house is pulled around, it becomes like an anchor to him. Eventually the anchor turns into a burden, and Carl has to make a choice between the past and the present/future.

First, he gives up his old furniture and pictures and remembrances to lighten the house so he can save both Russell and Kevin (the bird). Eventually, he lets go of the house... the anchor to Ellie--the anchor that keeps him from enjoying his life--the anchor that keeps him in the past, and keeps him from enjoying the present.

A floating house--a brilliant symbol.