Updating a cart on Airstrikeinc.com is simple. Just follow these steps:
Select "Cart" at the top right corner of the page, or go here https://www.airstrikeinc.com/cart
To add more of an item push the + symbol next to the quantity number, to subtract more of an item push the - symbol on the left side of the quantity number.
To remove the item completely from your cart click the "remove" link under the quantity.