You must follow the TSA's 3-1-1 protocol when packing liquids, gels and aerosols for travel. The 3 stands for the 3.4-oz. or smaller bottles the TSA permits for liquids. The first 1 refers to the one clear, quart-sized, zip-top bag that you must use to carry your bottles. The second 1 indicates that the TSA allots each individual traveler one quart-sized bag. The TSA notes that if you have doubts about your liquid items, save time and trouble by putting them in checked baggage. Some items, though, are exempt from the 3-1-1 regulation. For instance, if you clear medications, baby formula, baby food and breast milk with security checkpoint officials before proceeding through security, you can carry these items on in larger quantities, as long as the amount is "reasonable" for the length of your trip.
While the TSA sets guidelines regarding liquid items, individual airlines make the rules for how many carry-ons you can bring aboard a flight. A May 2010 search of major carriers in the United States revealed that the airlines' carry-on policies are similar. United Airlines' carry-on stipulations are representative of industry practice. United allows passengers one carry-on bag as well as an additional personal item for all flights. The carry-on bag must fit underneath the seat in front of you or in an overhead bin. Personal items include laptops, purses and briefcases. You may bring other items aboard the aircraft that do not count against your one bag/one personal item limit. For instance, United--and most other airlines--allow you to bring assistive devices, such as canes and crutches, child safety restraint devices, coats, hats, a "reasonable" amount of reading material, an umbrella and food and drink that you plan to consume aboard a flight.
On its website, the TSA provides an extensive list of what they allow you to put in carry-on and/or checked baggage. With the exception of standard lighters, which you are only able to carry on, the TSA prohibits all flammable items from both carry-on and checked luggage. Martial arts and self-defense items, such as Billy clubs and Nunchakus, as well as large sporting goods, including golf clubs and hockey sticks, are allowed in checked baggage, but not in carry-ons. You must check most tools, but the TSA does allow you to bring tools (e.g., screwdrivers, wrenches) that are 7 inches or less in length aboard an aircraft.
