The format of the notes in Planner works well with Allout mode, which provides helpful commands for navigating and formatting outlines. You can, for example, hide the bodies of all the notes on a page so you can see just their headlines. You can also jump easily from headline to headline, skipping over the bodies in between.
The commands for using Allout mode vary depending on which Emacs version you are using. In either case, type M-x load-library <RET> allout <RET> to start. If you are using Emacs 22 or later, type M-x allout-mode <RET>. If you are using an earlier version of Emacs, type M-x outline-mode <RET>.
The exact commands then available to you differ depending on your Emacs version, but you can view the commands and their keybindings by typing C-h m. In Emacs 22 or later, they will start with allout-, while in previous versions, they will start with outline-.
For more information about using Allout mode, see C-h f allout-mode <RET>.