"...Can you bring on an unopened soda onto a plane these days?..."
Looking at the TSA website, I would have to guess that you can not (unless bought after the checkpoint). They make no mention of canned drinks specifically, just beverages in general, and the 3 oz rule applies. Same with canned soups/whatever...
TSA site Item Carry-on
Beverages brought from home or purchased before reaching the security checkpoint in containers LARGER than 3 oz. No
Canned or jarred goods such as soup, sauces, peanut butter, fruits, vegetables and jellies Yes - 3 oz. or smaller container No