As beee said everything I used is above.
The functions.php I used was exactly as listed above.
For the template here is my version with the actual template code removed:
<?php
/*
Template Name: Property Page
*/
get_header();
if ( get_query_var( 'subpage' ) ) {
// if ?subpage=flyer is used, load the content for flyer-1
?>
<?php the_post(); ?>
<!-- ==================== -->
<!-- flyer/subpage code here -->
<!-- ==================== -->
<?php
} else {
?>
<!-- ==================== -->
<!-- main page code here -->
<!-- ==================== -->
<?php
while ( have_posts() ) : the_post();
the_content();
endwhile; // End of the loop.
?>
<?php get_footer(); ?>
<!-- ==================== -->
<!-- end landing page section -->
<!-- ==================== -->
<?php
}//end else
?>
