The smaller of your two carry-on bags is called a personal item. Common personal items include purses, computer bags, diaper bags, collapsible backpacks, briefcases and camera bags. Carry-on bags will fill the overhead bins if your flight is full, so your personal item must be able to fit underneath the seat in front of you, restricting its size. Each airline enforces a slightly different size restriction for personal items, but you can count on about 40 total inches. No U.S. domestic airline charges for bringing a personal item on board the aircraft.
Your main carry-on bag must fit inside the overhead compartment above your seat. Each airplane has different sized overhead compartments, so size restrictions vary slightly between airlines, with an average of 45 to 50 total inches. Most airlines allow you to carry on one bag for free. Some airlines, such as Spirit and Frontier, charge for carry-on luggage. These airlines generally give discounts to those who pay online before heading to the airport, and impose enormous fees at the gate for those who try to sneak a bag on board.
Pack your bag, throw it right-side-up on your kitchen table and get out a measuring tape. Measure the height, length and width. Record the individual measurements and add them up. That is your bag's size in total inches. You can look up carry-on size restriction on your airline's website. You can also size your bag up at the check-in area at the airport. Airlines provide what looks to be a cage sitting on the floor with a sign about carry-on bag sizes. Put your bag inside this frame to see if it fits. If it does, you are good to go.
TSA screens all carry-on bags and items -- including belts, hats, jackets and shoes -- in an effort to keep the flying public safe. The agents look for and seize potentially dangerous items. These items include sharp objects, blunt sports equipment, any kind of firearm, tools that are more than 7 inches long, explosives and flammable items. They also prohibit liquids and gels in bottles over 3.4 ounces. But you can bring ice skates, common lighters, snow globes and liquids inside bottles that are 3.4 ounces or less. You are allowed to fill a single 1 quart plastic bag with as many small liquid bottles as you can fit, and that's the limit.
Lugging your carry-on bag from gate to gate during a connection can be a physically challenging hassle, especially if you are at a large airport like Atlanta or Chicago O'Hare. Ask to gate-check your carry-on bag with the agent at the boarding gate after you get it through security. The agent will tag your bag and you will leave it at the end of the boarding tunnel right before you get on the plane. The bag will then go underneath the plane and be waiting in baggage claim at your final destination. This way, you can enjoy your connecting airport instead of dreading it.
