There are times that you want to stray from the regular permalink structure that WordPress applies to your custom post types.  For a recent project I was needing to remove the CPT slug from the permalink, so a page url like  “/events/some-event-slug/” would have the permalink of “/some-event-slug/.”  At first glance this doesn’t seem to be that difficult to accomplish, but then you start looking through the WordPress.org forums for a solution and come back with several different “solutions” and none of which work for you. Then there are time you find a script that just works, and that is what I am sharing with you.

Thanks WordPress VIP for posting a solution.

Just paste the following code in your functions.php file and replace “your_post_type” with the slug of the post type you wish to drop the slug from.

/**
 * Remove the slug from published post permalinks. Only affect our CPT though.
 */
function vipx_remove_cpt_slug( $post_link, $post, $leavename ) {

    if ( ! in_array( $post->post_type, array( 'event' ) ) || 'publish' != $post->post_status )
        return $post_link;

    $post_link = str_replace( '/' . $post->post_type . '/', '/', $post_link );

    return $post_link;
}
add_filter( 'post_type_link', 'vipx_remove_cpt_slug', 10, 3 );

function vipx_parse_request_tricksy( $query ) {

    // Only noop the main query
    if ( ! $query->is_main_query() )
        return;

    // Only noop our very specific rewrite rule match
    if ( 2 != count( $query->query )
        || ! isset( $query->query['page'] ) )
        return;

    // 'name' will be set if post permalinks are just post_name, otherwise the page rule will match
    if ( ! empty( $query->query['name'] ) )
        $query->set( 'post_type', array( 'post', 'your_post_type', 'page' ) );
}
add_action( 'pre_get_posts', 'vipx_parse_request_tricksy' );

When that’s done be sure and update permalinks. That’s it.

See original post here:  http://vip.wordpress.com/documentation/remove-the-slug-from-your-custom-post-type-permalinks/