If you want to remove all countries (options) and add only selected or specific country as per your need in the country field (dropdown) under traveler info and billing address form in checkout page then worry not,  WP Travel  includes the feature that allows you to use filter code to remove all countries and add only specific country as per your requirement on the Checkout page.

To remove all countries and add only selected country on the checkout page, you have to add following given filter code in functions.php file of your child theme.

function wp_travel_customized_countries( $countries ) {
return array( 
    'AF' => __( 'Afghanistan', 'wp-travel' ),
    'AN' => __( 'Angola', 'wp-travel' ),
    'NZ' => __( 'New Zealand', 'wp-travel' ),
);
}
add_filter( 'wp_travel_country_list', 'wp_travel_customized_countries' );

For detail assistance regarding creating child theme, please refer link.

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