An infant at Edinburgh Airport held onto his bag of baby formula. (photo credit: David Cheskin/Press Association)
Since August 2006, the Transportation Security Administration (TSA) has relaxed its carry-on security measures for all U.S. flights and passengers. Aerosols, liquids, and gels are now allowed in carry-on luggage so long as they do not exceed 3.4 ounces (100mL) in volume. Each item must be placed in a clear, quart-sized zip-top bag and only one of these bags is allowed per passenger.
There are exceptions, however: U.S. passengers traveling with a baby or small child may bring baby formula, breast milk, or juice onboard in reasonable quantities exceeding 3.4 ounces. These items do not have to be packed in a clear zip-top bag but must be declared at the security checkpoint for screening. Other permissible liquids include prescription medicine with a name that matches the passenger's ticket, insulin, and essential non-prescription medicines.
For more information on the airport security measures in the U.S., visit the TSA website.