A carry-on bag is most people's security blanket, best friend and lifeline when traveling. Your carry-on often has essentials for the airplane. For me, that means snacks and entertainment, but a carry-on should also include valuable, hard-to-replace items such as passports, prescriptions, toiletries, cash and clothes in case your checked luggage gets lost. Believe me, packing a day or two extra clothes saved me when my suitcase was lost on the way to London.Following Transportation Security Administrationguidelines for each major US airline is also a must and doing a little research on the latest rules and regulations can help you ace the experience without getting held up. What TSA officials confiscate isn't in your control, but what you pack and how you pack it is in your control. Here's how to pack your carry-on bag efficiently for your next business or pleasure travel.For more travel tips, explore these travel essentials you need for every vacation and then take a look atthis travel checklist. The best carry-on travel bags Before you start packing, you'll have to find the right carry-on bag. Here are a few important things to keep in mind. What size carry-on should you get?The first and most important aspect to think about is size. Federal Aviation Administration regulations say carry-on items can't exceed dimensions of 22 by 14 by 9 inches, though you might find an inch or two of difference depending on the airline. The general rule is that it must fit under your seat or in the overhead enclosed storage compartment on the plane. Here's a quick reference for size limits for the most popular US airlines. Carry-on items by airline AirlineCabinMaximum size Air Canada All55 x 40 x 23 cm; 21.5 x 15.5 x 9 inAlaska Airlines All55.88 x 35.56 x 22.86 cm; 22 x 14 x 9 inAmerican Airlines All56 x 36 x 23 cm; 22 x 14 x 9 inBritish Airways All56 x 45 x 25 cm; 22 x 18 x 10 inDelta Air Lines All56 x 35 x 23 cm; 22 x 14 x 9 inFrontier Airlines All60.96 x 40.64 x 25.4 cm; 24 x 16 x 10 inHawaiian Airlines All55.9 x 35.5 x 22.9 cm; 22 x 14 x 9 inJetBlue Airways All55.88 x 35.56 x 22.86 cm; 22 x 14 x 9 inSouthwest Airlines All60.9 x 40.6 x 25.4 cm; 24 x 16 x 10 inSpirit Airlines All56 x 46 x 25 cm; 22 x 18 x 10 inUnited Airlines All56 x 35 x 22 cm; 22 x 14 x 9 in Carry-ons should have an easy access tech compartmentIf you decide to bring electronics like a laptop, iPad, Kindle or other tablet on board, your carry-on should ideally have a separate, padded compartment for secure packing. Be sure these compartments are easily accessible, since at security checkpoints, the TSA will require you to remove your electronic devices and place them in the plastic X-ray tray. Make sure you're carry-on is comfortable on your back or shoulderRemember, you'll need to lug your carry-on bag or suitcase across the airport and down long corridors, and you might even need to run with it so you don't miss your connection. Consider whether you need padded handles or cushioned straps or a backpack or a rolling suitcase for ease. The general rule is that all carry-ons must fit under your seat or in the overhead enclosed storage compartment on the plane. Getty Images How to pack your carry-on the right way Though what to pack in your carry-on ultimately depends on your preferences, there are a few guidelines for the best way to pack your luggage: Pack items in layers (shoes one layer, clothes one layer, electronics one layer, etc.).Pack the things you'll use the least at the bottom of the bag.Keep most of your valuables in your carry-on luggage, and store them in side compartments or safely padded around other items.Place valuables at the bottom of your bag, away from the opening.Keep your wallet, credit cards and cash in an inner pocket so they'll be harder to steal.Pack a small, separate bag for toiletries. (Liquids, gels and aerosols packed in carry-on must follow the3-1-1 liquids rule: 3.4 ounces or less per container; all liquids must fit in one quart size, clear, plastic, zip-top bag; one bag per passenger.)Roll your clothes tightly to save space in your luggage.Sometimes you lose your luggage. It happens. Though it's frustrating, it's important to pack a spare set of clothes (including socks and underwear!) in your carry-on to hold you over until your bags are found and returned. Pack clothing that can easily be rolled up and put in the bottom of your bag. Rolled clothing can save space in your tight bag or suitcase. Getty Images Essential items for your carry-on bag There's some items that are just better in your carry-on luggage. If you do decide to check a bag, be sure to keep these items with you on the flight. Most of these carry-on essentials are items that would be hard to replace or purchase when you get to your destination. Prescriptions and medicationsContact lenses or glassesValuables like jewelry, wallets, passports, IDs and boarding passesCameras and smartphonesEntertainment like tablets, books and laptopsHeadphones to watch TV or movies if a longer flightChargers for electronicsPrinted itinerary, or hotel and flight confirmationsExplore this complete guide for essential travel items you may forget to pack. Place your larger electronics in secure yet easily accessible compartments, since you'll need to pull them out at TSA security checkpoints. Getty Images What you should never pack in your carry-on bag The TSA has specific guidelines covering which items are banned from flights and the agency takes those rules very seriously. In 2022 alone, the TSA screened nearly 761 million passengers and crew members nationwide, and it confiscated a record number of firearms (6,301) and many other items. TSA policy says that individuals carrying weapons, especially loaded firearms, can face fines or criminal penalties. These are some of the most commonly confiscated items: FirearmsFireworksBox cutters, utility knives and razorsBats, clubs and bladesSwiss Army knivesSharpIf in doubt, always refer to theTSA's guidelines on packing for flights, to ensure you have safe and easy travels. If you're planning a vacation soon and are stressed about packing or preparing, CNET has plenty of resources to help. Get ready for your next trip with these hacks and tips: