How to activate all arms

I want to destroy all my navy fighters and I have 200 deactivated, is it possible to destroy deactivated arms? How can I activate them all at once?

They have to be active. You can only activate 10% at a time each month. The only way around it is to direct sell the inactive weapons to one of your countries. You could then destroy them in the other country. (You can also sell them to an enterprise but you can't destroy them there.)
I usually sell inactives to another country when I get down to very low numbers because it is annoying to reactivate 2 or 3 weapons at a time.

Alright, thank you but how do I sell them to other countrys or enterprises?

Trade > Trade with countries or enterprises

Click the link, select the category (offense or defense weapons) and follow the directions from there.

Once you submit the order to sell them, you have to go into the country you sold them to and go to Trade > Trade with countries or enterprises and accept the offers. Then you will be able to destroy the weapons.

You can also offer the weapons for sale on the market, even if they are inactive. You do this by going to Trade > Products in stock buy or sell. Then find the item and offer it for sale on the open market.

Thank you so much!