Just under 770 million passengers flew on domestic and international flights from the United States in 2009, according to the Bureau of Transportation Statistics. Rules relating to items prohibited from planes are much the same for both international and domestic flights, and your airline might impose its own additional restrictions.

3-1-1 Rule

The Transportation Security Administration's simple 3-1-1 rule helps you remember which liquids you can take onto a plane in your cabin baggage. The “3” indicates the 3 oz. bottles you can bring with you, while the two “1”s represent the single, clear, 1 quart zip-top plastic bags you can carry the bottles in. Although the TSA developed this rule in 2006 for domestic flights, it has since been recognized internationally. Pack larger volumes of liquid in your checked baggage.

Cabin Baggage

Besides the 3-1-1 rule governing liquids, other restrictions exist on what you can bring in your cabin baggage. The TSA website provides a full list, but generally you cannot bring any potentially dangerous objects into the cabin. This includes items like box cutters, baseball bats, hammers and martial arts weapons. If necessary, you can carry most of these items in your checked baggage, although if they are sharp you should ensure they are packed securely to prevent baggage handlers from being injured. Your airline also will have its own rules on the size, shape and quantity of cabin baggage you can bring; check these regulations in advance.

Checked Baggage

Although you have much greater freedom in what you pack in your checked baggage, some restriction still exist, mainly relating to explosives. Items like flares, gunpowder and any type of explosive or flammable material are prohibited. The list of prohibited items also includes many types of lighters, flammable paints, chlorine, compressed fire extinguishers and self-defense sprays. These rules are subject to change, so check the TSA website before your trip to make sure you’re up to date.


Security and airline staff are able to make exceptions in specific cases such as people with medical needs or disabilities. These exceptions include life-support liquids like blood and bone marrow, liquid nutrition, and prescription and over-the-counter medicines. Passengers traveling with children also can carry on liquids above the 3-1-1 limits, and although you must declare these items at security, you should not be asked to taste them. If you are unsure in any way, check with your airline before traveling to the airport.