Flying to that annual family get-together? Don't turn your airport security agent into an unwitting Scrooge. Checkpoint personnel don't really want to dampen your holiday cheer -- or their own -- by taking away presents. So here's a checklist of what you can and cannot bring on board an airliner. Because no matter how much your dad will love that 16-ounce bottle of cologne, the Transportation Security Administration certainly will not if it's in your carry-on. This holiday season, remember the 3-1-1 rule for liquids: Bottles of liquid must contain 3.4 ounces (100 ml) or less and be placed in a quart-sized, clear plastic, zip-top bag; each passenger is allowed one such bag. Just be glad Santa has his own way to fly.