This hook allows you to add your custom content just above the tabs section of single trip page.

Source

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

Introduced on WP Travel version 2.0.4over wp_travel_after_single_itinerary_header.

Example :

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