Good evening Maarten and welcome to the Events Calendar forum!
Thank you for your interest in our products and we’ll be glad to answer your question.
I also want to sell tickets using Woocommerce. Is this add-on part of the PRO package?
The short answer is no unfortunately. The PRO package is awesome and contains many great features, 1 year of updates and support (as I am sure you are well aware of).
To be able to sell tickets through WooCommerce, you will need the Events Tickets Plus premium add-on which works completely separately from the Pro premium add-on. In other words, you can buy you do not need one to run the other, but they work great together 🙂
Let me know if that helps.
Have a great day!
Geoff B.