This hook allows you to add your custom text just above the title of the trip in single trip page.

Source

File : /templates/content-single-itineraries.php

Example :

function prefix_wp_travel_before_single_title( $post_id ) {
    esc_html_e( 'This is the content added using this hook', 'text-domain' );
}
add_action( 'wp_travel_before_single_title', 'prefix_wp_travel_before_single_title'  );