Carry-on luggage is luggage that you take on to the plane with you. Each passenger is allowed to carry on one small piece of luggage and one small item such as a purse or laptop.
When packing your carry-on, do not include items that can be potentially dangerous, such as scissors, which will not be allowed through the security checkpoint.
Checked luggage is luggage that you drop off when you check-in at the airport. It will not be accessible during your flight. Each airline has different limits for the size and weight of checked luggage. The most common restriction is two bags, each weighing 50 lbs. or less per person. Weight limits are often different for international flights.
Most airlines charge a fee for checked luggage. Sometimes this fee is smaller if you pay it before arriving at the airport.
The Transportation Security Administration enforces a limit for how much liquid each passenger can have in his carry-on luggage. The agency's policy is called "3-1-1." Each passenger is allowed to fill one clear, quart-sized plastic bag with bottles containing liquid. Each bottle must be 3.4 oz. or less. You can travel with approved liquids that do not follow these regulations by placing them in your checked luggage.
Some liquids, such as medications and breast milk, can be taken onto a plane in larger quantities. If you need to carry on these liquids, you can ask for a special inspection when you reach the security checkpoint.
