Can I bring alcohol through ATL security?
Alcohol containers larger than 3.4 oz are not allowed through TSA security in carry-on bags. Bottles purchased at duty-free post-security are allowed.
Alcoholic beverages in containers larger than 3.4 oz / 100 ml are not allowed through TSA security in carry-on bags, in accordance with the standard liquid restrictions. Smaller bottles (e.g., the airline-style 50 ml miniatures) are permitted but must fit within your single quart-sized clear plastic bag along with other liquids and gels.
Alcohol over 70% alcohol by volume (140 proof) is not permitted in checked baggage either. Beverages between 24% and 70% ABV are limited to 5 liters per passenger in checked baggage and must be in unopened original retail packaging.
Alcohol purchased at duty-free shops post-security is allowed on board your initial flight. For connecting international flights, the duty-free purchase is typically packaged in a sealed STEB bag (Secure Tamper-Evident Bag) that protects the bottle from being flagged at your connection's security check.
Open containers of alcohol cannot be consumed on board unless served by the flight crew. Drinking alcohol you've brought on board (even from a duty-free purchase) is technically prohibited under FAA rules and can result in a fine.