This hook allows you to add your custom text just below the  “Trip Code” i.e at the bottom of the trip meta info section. 

Source

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

Example :

function prefix_wp_travel_single_trip_after_title() {
    esc_html_e( 'This is the content added using this hook', 'text-domain' );
}
add_action( 'wp_travel_single_trip_after_title', 'prefix_wp_travel_single_trip_after_title'  );