Most flights limit liquids and ban travelers from taking sharp and blunt objects on a plane with them in their carry-on luggage. Banned items include such sporting goods as baseball bats and hockey sticks, instead requiring that passengers check these items. There are some exceptions to the general guidelines, however. Luggage requirements can vary slightly from airline to airline, so always check with your carrier if there is any doubt.
Most countries have implemented what's called the 3-1-1 rule: non-flammable liquids, gels and aerosols must be in 3-ounce containers or smaller, and each passenger is allowed a single one-quart baggie filled with those items. The rule does not apply to liquids purchased beyond the security checkpoint, such as beverages bought to drink while in flight.
Most sharp objects--box cutters, ice picks and razor blades--are prohibited in carry-on luggage. Exceptions include safety razors, plastic or round-bladed butter knives and metal scissors with pointed tips and blades shorter than 4 inches. Other sharp objects must be wrapped or sheathed and packed in checked luggage.
In general, tools under 7 inches in length are acceptable to bring onboard, including screwdrivers, wrenches and pliers. Hammers, saws, drills, drill bits and hatchets are not allowed and must be checked in luggage.
Most weapons are banned from being taken on planes, including brass knuckles, martial arts weapons, clubs and stun guns. The single exception is mace or pepper spray. Passengers can bring one container, 118 milliliters or 4 fluid ounces or less in size, as long as it has a device to prevent accidental discharge.
Because of customs regulations, many fruits, vegetables and meats are not allowed on international flights, depending on the agriculture recommendations at the time of the flight. Baked goods and cheeses are usually allowed following an inspection. Food bought past the security checkpoint intended for onboard consumption is also acceptable.