A carry-on is the small piece of luggage that you're allowed to take on board a plane. The Transportation Security Administration limits each passenger to one carry-on in addition to a personal item such as a laptop, purse or briefcase. A carry-on should hold anything that you feel you need during your flight, along with a change of clothes in case your luggage is lost.

What to Pack
When packing a carry-on, it's essential to think about what items you'd be hard-pressed to do without. These are the things that should be in your small duffel bag or backpack. Choose a change of clothes that are not bulky. Roll them up to keep them from getting wrinkled and to make them as small as possible. Include prescription medications and basics like aspirin in case you need them. Carry your contact lens case and glasses in case the cabin air dries out your eyes. Rewetting drops are also a good idea, but place them with other liquids in a baggie. Buy a travel-sized toothpaste and put it in your carry-on with your toothbrush. You'll appreciate being able to brush your teeth after a nap on board. Don't forget a snack in your carry-on in case you get hungry during the flight or layover. If you're traveling with anything that's valuable such as jewelry, put that in your carry-on, too, in case you lose your luggage.

Liquids, Aerosols and Gels
The amount of liquid, aerosol and gel you're allowed to carry on an airplane is limited due to TSA requirements. Each passenger can bring on one clear ziplock bag full of their toiletries. The bag must be no more than quart-sized. Each liquid or gel is limited to a volume of 3.4 ounces or less. Keep the bag handy in your carry-on so you can easily and quickly pull it out. It must be placed on the security belt to be examined by the officer. Passengers who need to carry on baby formula, breast milk or medications should clear them first with security. They are not liable to the same restrictions.

SimpliFLY
The TSA advises you to SimpliFLY your carry-on to get through airport security faster. If you pack an organized carry-on with layered items, workers can check your bag more efficiently. The TSA recommends you put heavier items on the bottom of the luggage, followed by clothes, electronics, then more clothes. Roll or fold clothing to keep it neat and wrap any electronic cords around themselves or tie with a twist-tie to keep the from getting tangled. The neater and more organized your carry-on is, the easier the security checkpoint will be.