How to sort by event dat order?

I’m using a query to display events on a home page like this:

$args = array(
'post_type' => array('post','ai1ec_event'),
'orderby' => 'date',
'order' => 'DESC',
'post_status' => 'publish',
'posts_per_page' => 3,
'post__not_in'  => get_option( 'sticky_posts' )
                                            );
$query = new WP_Query($args);

I’d like to sort by the event date, not date of event posting, which this query doesn’t do. How is that done?
Site is here: https://nappaneechamber.com

https://www.ads-software.com/plugins/all-in-one-event-calendar/