Remember the 3-1-1 rule. Passengers are allowed to bring in one transparent, plastic, sealable bag. The bag must be 1 quart or smaller. Each individual item must be in 3.4 oz. (100 mL) or smaller container. This bag must be taken out of your luggage and placed on the belt in its own container. However, there are exceptions to the 3-1-1 rule: Passengers may bring, in “reasonable quantities”, medicine, baby formula and food, and breast milk. A reasonable quantity is not defined; it is up to the TSA Officer’s individual discretion. The 3-1-1 rule was implemented in September 2006 after UK authorities uncovered a plot to blow up a large number of airplanes with sports drinks mixed with other chemicals. Initially, the TSA banned all liquids from carry-on luggage but arrived at the 3-1-1 after rigorous testing. Aerosols are banned from checked and carry-on baggage. However, you may pack toiletry aerosol items in your carry-on luggage. You may bring vaping devices and electronic cigarettes in a carry-on, but you are not allowed to place them in your checked baggage. You may also bring safety matches or lighters without fuel in a carry-on, but not in checked baggage. Other prohibited items include chlorine, fireworks, spray paint, strike-anywhere matches, and turpentine. For a full list of prohibited items, please see the TSA’s website . Identification Starting on January 22, 2018, states who have not complied with the REAL ID Act will no longer have valid drivers licenses for purposes of the TSA and other federal agencies. Some states have already been granted extensions until October 1 2020, but passengers from the following states and territories will need an alternative form of ID: New York, Illinois, Missouri, Michigan, Louisiana, Rhode Island, Puerto Rico, U.S. Virgin Islands, Northern Mariana Islands, American Samoa, and Guam. Also starting on January 22, 2018, TSA will no longer attempt to ascertain the identities of passengers who do not bring identification. Previously, passengers who lost or forgot their IDs could submit to an interview and more intensive screening process where the TSA could allow a passenger through if their identify was ascertained.