The TSA and governments around the world enforce strict regulations for carry-on baggage on international flights. Items that could cause danger to yourself or compromise the safety of other passengers are banned. These include firearms, weapons, items with sharp edges, or flammable or explosive items. Sporting goods that could harm others are also not allowed. Despite the restrictions, passengers can transport many other things in their carry-on baggage. Just be aware of the airline's limitations before you fly.

Size Matters

The smaller the carry-on bag, the better. Baggage allowance differs depending on whether you are flying in economy class, business class or first class. Usually, airlines allow business and first-class passengers to carry heavier bags than passengers in economy. American Airlines and KLM Dutch Airways say that passengers in economy can take bags with dimensions of 45 inches or less and that weigh less than 26 lbs, while passengers in first or business class can take bags with dimensions of 45 inches or less that weigh less than 40 lbs. Some airlines also allow you a personal item in addition to your carry-on baggage, such as a laptop or a backpack, although it is always worth checking your specific airline's rules before traveling.

Take Your Meds

Although items such as syringes and large liquid containers are not usually allowed on aircraft, passengers who need certain medications may take necessary medical items on board. You will need to show a valid prescription or physician's note at the airport to be allowed to take these on an airplane.

Watch the Liquids

Liquid containers that fit the TSA's "3-1-1" rule are allowed in carry-on baggage. Each liquid container should be 3 ounces (100 ml) or less; all liquids must fit in a 1-quart bag and passengers can take one of these bags on board per traveler. This means you can take cosmetics, creams and toiletries in your carry-on baggage, provided they adhere to airline rules (i.e., each item should be in a container of 3 ounces or less and the total number of vessels should fit into a single 1-quart bag). Exemptions to this rule include liquid medication and baby food, including quantities of breast milk, formula or juice that exceed the 3-ounce restriction.

Listen to Electronics

Passengers are allowed to take personal electronics on board, provided they fit the airline's weight and size restrictions. These items include laptops, personal audio systems, hand-held gaming devices and digital cameras. It can be safer to pack these items in your carry-on luggage, reducing the risk they might be lost, damaged or stolen. Most airlines place restrictions on passengers using electronic items during take-off and landing, but passengers are allowed to carry them in their luggage at all times.