The TSA allows passengers to bring limited quantities of alcohol on a plane, but it's got to be in a sealed container and in your carry-on bag. Don't even think about trying to sneak a flask onto the plane, those eagle-eyed security agents will catch you in no time. And, trust me, you don't want to end up on the no-fly list!
Now, you might be thinking, "What about duty-free shopping?" Well, let me tell you, that's a whole different story. When you buy duty-free liquor at the airport, it's usually sealed and packaged in a special bag, and you're allowed to bring it on the plane. But, be careful, because if you open that bag, you'll have to declare it and might even have to pay taxes on it - yikes!
The FDA also has some rules around bringing alcoholic beverages on a plane. For example, did you know that liqueurs are considered a restricted item? Yeah, it's true, so if you're planning on bringing your favorite Kahlúa or Baileys on the plane, you'd better check with the airline first. And, let me tell you, it's not worth the hassle, just buy it at your destination instead!