Include templates from plugin

plugin.php

define( 'PLUGIN_PATH', plugin_dir_path( __FILE__ ) );

//Template fallback
add_filter( "template_include", 'ps_theme_redirect' );

function ps_theme_redirect( $template ) {
    //cpt is the slug of the custom post type registered
    if ( get_post_type() == 'cpt' ) {
        if ( is_single() ) {
            //looks in the current theme directory for the template if so it is returned otherwise the template from the plugin directory is returned.
            if ( file_exists( get_stylesheet_directory() . '/single-cpt.php' ) )
                return get_stylesheet_directory() . '/single-cpt.php';
            return PLUGIN_PATH . '/templates/single-cpt.php';
        } else {
            if ( file_exists( get_stylesheet_directory() . '/archive-cpt.php' ) )
                return get_stylesheet_directory() . '/archive-cpt.php';
            return PLUGIN_PATH . '/templates/archive-cpt.php';
        }
    }
    return $template;
}