Each passenger on a commercial flight in the United States is allowed one carry-on bag that can have liquids in 3.4-ounce containers that all fit into one quart-sized plastic zipper bag, as of November 2014. Normal carry-on items such as clothes, personal consumer electronics, medicines and nonliquid personal hygiene items are allowed. All carry-on bags must be inspected at airport checkpoints.
Any liquids carried on board must fit in a 3.4-ounce container. This container must then fit into a clear, plastic zipper bag along with all the other liquids a passenger wishes to bring into the plane's cabin. Each person gets one such zip-top bag full of liquids, separated into containers holding 3.4 ounces or less. The Transportation Security Administration labels as liquids such items as perfumes, gravies, jellies, lotions, sauces and snow globes.
The rest of a carry-on bag can contain consumer electronics such as laptops, music players and tablet computers. Passengers are responsible for their own belongings, which are inspected by screeners. Some items prohibited in carry-on luggage are allowed on checked baggage that goes in the plane's cargo area, such as box cutters, razor blades, scissors, sporting goods and certain ammunition. Not all checked baggage is opened and inspected, but it does go through X-ray devices to view the bags' contents.