When you're packing, remember to limit anything liquid-y to 3.4 ounces (100 milliliters) or less and to place those items in a clear, quart-sized plastic bag, one bag per traveler. Think the usuals, like shampoo, toothpaste, and aerosol or roll-on liquid deodorant (solid deodorant isn't regulated by the 3-1-1 rule).

This is a "High-Fidelity" distinction that can save you a lot of hassle at the airport: Solid stick deodorant is NOT considered a liquid by the TSA and can be any size in your carry-on bag. However, roll-on, gel, and spray deodorants ARE considered liquids, gels, or aerosols. If your deodorant is a roll-on (the kind with the liquid ball at the top) or a gel, it must follow the 3-1-1 rule: the container must be 3.4 ounces (100ml) or less and it must be placed inside your single, quart-sized, clear plastic bag along with your shampoo and toothpaste. Many travelers accidentally get their large "gel" or "roll-on" deodorants confiscated because they assume "all deodorant" is a solid. If you want to avoid the liquid bag entirely, stick to the firm, opaque "dry" sticks, which are treated as solids and don't count toward your liquid limit. Always check the physical state of the product—if you can squeeze it, spray it, or roll it as a liquid, it belongs in the plastic bag.