Items on the TSA's restricted or prohibited list are those which are never permitted to be carried on a plane. Passengers may carry on liquids, aerosols, gels, creams and pastes so long as they are stored in containers that do not exceed 3.4 ounces, and these containers must fit into one quart-sized bag. These items may still be subjected to additional screening.
There are many items that are prohibited from being transported as carry-on, however, some of them may be transported in checked baggage. Each airline, following TSA regulations, has established a policy regarding the transportation of such items. Certain items, such as unloaded firearms, may be transported in checked baggage but must unloaded and safely stored in a locked, hard-sided carrying case. Even when items are generally allowed to be transported, they may still be subject to additional security checks and, under TSA discretion, may not be allowed through certain checkpoints if an issue is found. If these items set off any additional alarms or raise security concerns, they may not be allowed on the flight.
There are exemptions to the liquids rule for travelers with transporting medically necessary liquids, medications and creams. Travelers should Inform the TSA officer of these items and separate them from other belongings before the security screening begins.
Passengers who attempt to carry on prohibited items can be faced with fines or may face an arrest.