You can carry on as many 3 oz. or smaller liquid containers as you can fit into a quart-size clear plastic bag.
Medication, food, and baby formula or breast milk aren't covered by liquid security rules, although they'll have to be looked over at the security checkpoint.
In general, if it's something sharp and pointy---such as a box cutter, knife or blade---you can't carry it on. Firearms and other weapons are also prohibited.
Gel candles and gel shoe inserts are banned from carry-on luggage by the Transportation Security Administration.
Carry-on size regulations differ by airline. Check with the airline before you travel.
