When it comes to packing your carry-on luggage and clearing TSA checkpoints, the same 3-1-1 rule that applies to toiletries also applies to liquor. You can pack small bottles of alcohol that are 3.4 ounces or less in a clear, quart-sized bag. If you have already passed through the security checkpoints and decide to buy alcohol at a duty-free store inside the airport, make sure to keep your receipt and don’t remove the bottle from the sealed bag provided at checkout.