functions.php

<?php

function limit_booking_types( $booking_types ) { 

	if ( is_admin() ) {
		return $booking_types;
	}

	$booking_types     = array(); // Clear previous contents of variable.
	$group_only_days   = 'Only Days';
	$group_date_time   = 'Date & Time';
	$group_multi_dates = 'Multiple Dates';

	$booking_types['multiple_days'] = array(
		'key'   => 'multiple_days',
		'label' => __( 'Multiple Nights', 'woocommerce-booking' ),
		'group' => $group_only_days,
	);

	$booking_types['date_time'] = array(
		'key'   => 'date_time',
		'label' => __( 'Fixed Time', 'woocommerce-booking' ),
		'group' => $group_date_time,
	);

	$booking_types['multidates_fixedtime'] = array(
		'key'   => 'multidates_fixedtime',
		'label' => __( 'Dates & Fixed Time', 'woocommerce-booking' ),
		'group' => $group_multi_dates,
	);

	return $booking_types;
}
add_filter( 'bkap_get_booking_types', 'limit_booking_types', 10, 1 );

function bkap_hide_extra_options() {
	?>
	<style type="text/css">
		.bkap_type_box{
			display: none;
		}
	</style>
	<?php
}
add_action( 'wp_head', 'bkap_hide_extra_options' );