Custom post type in Loops

Hi.

I’m trying to get a custom post type (called “travel-directory”) into a loop, where the regular blog posts are shown so far.

I tried a lot of stuff (e.g. this), but couldn’t get it to work. I would be very happy if somebody could help me.

Here’s the part where I want the custom post type to be included:

// The Query
$args['posts_per_page'] = $posts_per_page;
if (!empty($categories) && $categories[0] !== 'none') {
	$args['category__and'] = $categories;
}

$the_query = new WP_Query( $args );

// The Loop
if ( $the_query->have_posts() ) {

	?>
	<section class="regular <?php echo esc_attr($blog_class) ?>" <?php echo  $styles; // escaped above ?>>
		<div class="container">

			<div class="title-row">
			  <?php if (!empty($section_title)) : ?>
				<h3 class="title-entry"><?php esc_attr_e($section_title) ?></h3>
			  <?php endif; ?>
			  <?php if (!empty($category_link) && !empty($section_more)) : ?>
				<a href="<?php echo esc_url($category_link); ?>" class="btn btn-primary btn-xs"><?php esc_attr_e($section_more) ?> &nbsp; <i class="fa fa-angle-right"></i></a>
			  <?php endif; ?>
			</div>

			<div class="row">
				<?php
				while ( $the_query->have_posts() ) : $the_query->the_post();

					get_template_part( 'content-post'.$template_part, get_post_format() );

				endwhile;

				/* Restore original Post Data */
				wp_reset_postdata();

				?>
			</div> <!-- /.row -->
		</div> <!-- /.container -->
	</section>

	<?php

} // end have_posts()

Thanks!