Hello,
Regarding your query, as you can see in the screen record below, everything is working fine but you have skipped the cart page and after clicking ‘book now’ it takes you to the checkout page.
https://www.loom.com/share/3c54433d6faa49bcb97009eb70ece324
If there are any issues, please once disable the ‘skip cart page’ following the path Admin Panel > WP Travel > Settings > Cart and Checkout as shown in the screenshot below.
https://prnt.sc/stfazb
After you disable the ‘skip cart page’, it will display the cart page so that we can inspect the issue you have mentioned.
Also, please refer to the documentation link given below for detailed assistance on the empty cart issue.
https://wptravel.io/faq/#empty-cart-issue
Hope this helps.
If you have further queries, kindly let us know.
Regards.