[Plugin: Custom Post Type UI] Filter loop by categories

Thanks for the plugin, very neat.

I have created custom post type called “Products” with three different categories in it: “Cars”, “Planes”, “Bikes”.

I can easely list all the products on a custom template with:

$loop = new WP_Query( array( 'post_type' => 'products', 'posts_per_page' => 10 ) );
while ( $loop->have_posts() ) : $loop->the_post();
  the_title();
  echo '<div class="entry-content">';
  the_content();
  echo '</div>';
endwhile;

How do I filter the loop by categories for example just to get the cars?

can I add something like ‘post_category’ => ‘cars’ ?

Thank you!