• Travelers should be prepared to have their carry-ons searched prior to boarding the plane.vintage luggage image by Paul Hill from Fotolia.com
  
  Whether flying internationally or domestically, travelers face a variety of restrictions when it comes to their luggage. These restrictions can vary from airline to airline and often depend on the traveler's destination and the type of ticket purchased. For instance, passengers traveling in business or first-class may be allowed to check an extra bag for free, while those in economy class would incur an additional fee. Despite the variations between airlines, each passenger will face limits on luggage size and weight, allowed carry-on items and types of articles that cannot be packed.
  
  

TSA Restrictions

• The Transportation and Security Administration (TSA) maintains a list of prohibited items for both carry-on and checked luggage that applies to all flights. Prohibited items include sharp objects, guns and firearms, martial arts and self-defense items, explosive and flammable materials, disabling chemicals and other dangerous items. Sporting goods and tools are only permitted as checked items.
  
  In carry-on luggage, the TSA also restricts the amount of liquids, gels and aerosols to 3.4-ounce containers, all of which must fit into a single, one-quart, zip top, clear plastic bag per person. Medications, baby food, formula and breast milk are allowed in reasonable quantities that exceed three ounces and do not have to be stored in a zip-top bag. However, these items must be declared for inspection at the security checkpoint.
  
  As of 2010, cigarette lighters, nail clippers, nail files, safety razors, tweezers and scissors with blades shorter than four inches in length may be packed in carry-on luggage.
  
  

Carry-On Luggage Restrictions

• Restrictions for carry-on luggage are relatively consistent across all airlines. Most airlines limit travelers to one piece of carry-on luggage with dimensions not exceeding 45 inches, when length, width and height are combined. This piece must fit comfortably underneath the airline seat in front of the passenger or in the overhead bin.
  
  In addition to one carry-on bag, passengers may also bring one personal item on board, such as a purse, briefcase or laptop computer.
  
  Travelers may also carry on items such as child safety seats, infant restraint devices, coats, umbrellas, reading material and assistive devices, such as canes or crutches. These items do not count toward the passenger's carry-on baggage limit.
  
  

Checked Luggage Restrictions

• Restrictions on checked luggage vary slightly from airline to airline and often depend on the flight's destination and the passenger's ticket. Economy passengers on domestic flights will are typically charged $25 for their first checked bag and $35 for the second. Most airlines allow business and first-class travelers to check up to three bags at no charge. Each checked bag should not exceed 50 pounds and 62 linear inches. International travelers face the same weight and size restrictions, but are typically allowed one to two checked bags without incurring additional fees.
  
  On both domestic and international flights, any oversize, overweight or excess baggage will be subject to additional fees. For instance, American Airlines charges economy passengers $100 for the third, fourth and fifth checked bags and $150 for each additional bag after that.
  
  Passengers must also be careful when purchasing and packing duty-free items. Items that were delivered to the aircraft for passenger pick-up, bought on the plane or purchased after the security checkpoint are allowed and will not be confiscated upon arrival in the U.S. If travelers have a connecting flight within the U.S., however, liquid duty-free purchases must be placed in checked baggage.
  
  While baggage locks are still allowed, passengers should choose a TSA-approved lock, which can be opened with a universal master key by security officers. Non-TSA-approved locks will be cut, should the bag be physically inspected.