According to the TSA's "3-1-1" rule, which remains the standard in 2026 despite the introduction of advanced 3D scanners in some airports, each passenger is allowed exactly one clear, quart-sized, zip-top bag for liquids, gels, and aerosols. This "one-bag" limit is strictly enforced per person. If you are traveling as a family, each member (including children) is allowed their own individual quart-sized bag. Inside this bag, all containers must be 3.4 ounces (100ml) or smaller. If you have two quart-sized bags for yourself, security will require you to consolidate them into one or discard the excess. The only common exceptions to this rule are for medically necessary liquids (like insulin or IV bags) and baby formula or breast milk, which can be carried in larger quantities and do not need to fit inside the quart-sized bag, though they must be declared to the TSA officer for separate screening. Always remember that "quart-size" is the maximum; using a smaller bag is fine, but using a gallon-sized bag will result in a secondary search and potential confiscation of your items.