Your carry-on is your most important bag. Whether it’s your only bag or a supplement to a checked suitcase, knowing exactly what belongs inside makes every flight smoother and every disruption more manageable.
The Rules First
Carry-On Size & TSA Rules
Before packing anything, know the limits. Carry-on rules vary by airline and are enforced more strictly than ever.
Standard U.S. airline carry-on dimensions
Most major U.S. airlines (American, Delta, United, Southwest) allow a carry-on bag up to 22″ x 14″ x 9″ including handles and wheels. This fits in the overhead bin. You also get one personal item (purse, laptop bag, or small backpack) that fits under the seat in front of you — typically up to 18″ x 14″ x 8″. Always check your specific airline’s current policy as dimensions and enforcement vary. Budget carriers and regional jets often have stricter limits.
TSA liquid rules (3-1-1)
All liquids, gels, creams, and aerosols must be in containers of 3.4 oz (100ml) or less. All containers must fit in one quart-sized clear zip-top bag. One bag per passenger. This applies to: water, shampoo, conditioner, lotion, toothpaste, makeup, sunscreen, and anything else liquid or gel-like. Solid items — deodorant sticks, solid shampoo bars, powder makeup — do not count as liquids. Exception: medications and baby formula are allowed in larger quantities and should be declared separately.
What TSA will confiscate
Sharp objects over 4 inches (scissors, knives, box cutters). Liquids over 3.4 oz. Firearms and ammunition (must be checked and declared). Flammable items and compressed gases. Lithium batteries over 100Wh (most laptop batteries are fine; check yours). Spare lithium batteries must be in carry-on — they cannot go in checked bags. When in doubt, check the TSA’s “What Can I Bring?” tool at tsa.gov.
Never Check These
Items That Always Go in Your Carry-On
These items should never go in a checked bag — even if you’re checking luggage. If your checked bag is lost or delayed, you’ll be glad these are with you.
Valuables and irreplaceables
Passport and all travel documents. All medications — prescription and over-the-counter. Electronics: laptop, tablet, camera, and all batteries. Jewelry and items of sentimental value. Cash and all credit/debit cards. Your phone and charger. Keys. Anything that would be catastrophic or very difficult to replace if your checked bag were lost.
Lithium batteries — required in carry-on
TSA and FAA regulations require all spare lithium batteries (including portable battery packs, spare laptop batteries, and camera batteries) to be carried in carry-on bags — not checked. This is a safety regulation, not just a guideline. Installed batteries (the one in your laptop or phone) can go in checked bags, but spares cannot. This means your portable battery pack must always be in your carry-on or personal item.
One change of clothes
Even if you’re checking a bag, pack one complete change of clothes in your carry-on. If your checked bag is delayed — which happens far more often than people expect — you’ll have something to wear at your destination. This is especially critical for international trips or trips where you have an important event on arrival day.
The Complete Carry-On List
What to Pack — Item by Item
Documents & ID
Passport or government-issued ID. Boarding pass (screenshot it — don’t rely on app access alone). Hotel and car rental confirmations. Travel insurance policy card and emergency number. Known Traveler Number (TSA PreCheck/Global Entry) — add to your airline profile so it auto-populates. Emergency contacts written on paper (old-fashioned but works when your phone dies).
Health & medications
All prescription medications in original labeled containers — enough for the full trip plus extra days. Over-the-counter essentials: pain reliever, antacid, antihistamine, motion sickness medication if needed. Blister bandages and a few adhesive bandages. Hand sanitizer (3.4 oz or under). Any personal medical devices. Copies of prescriptions for controlled substances.
Tech & power
Phone and charging cable. Laptop or tablet if needed. All spare lithium batteries and portable battery packs (required by TSA — cannot be checked). One multi-port USB charging brick. Earbuds or noise-canceling headphones — a game changer on long flights. Universal adapter if traveling internationally. E-reader if you prefer physical reading. Earplug and eye mask for overnight flights.
Comfort items for the flight
Neck pillow (inflatable ones pack flat). Light blanket or large scarf — airplane cabins can get cold and the provided blankets are thin. Lip balm — cabin air is extremely dry. Moisturizer. Snacks: nuts, protein bars, dried fruit — airport food is expensive and options are limited. Empty reusable water bottle to fill after security. Chewing gum for ear pressure during descent.
Toiletries (3-1-1 compliant)
Travel-sized toothbrush and toothpaste. Deodorant (travel size). Face wash or cleansing wipes. Moisturizer. Any makeup essentials. Contact lens supplies if needed. All in one quart-sized clear zip-top bag, placed at the top of your bag for easy removal at security.
Clothing layer
One light layer — a cardigan, hoodie, or packable jacket. Airplane cabins vary dramatically in temperature and you rarely know which you’ll get. One pair of compression socks for flights over 4 hours — they reduce swelling and the risk of deep vein thrombosis on long hauls. Slip-on shoes make security much faster and are more comfortable during long flights.
Personal Item Strategy
Making the Most of Your Personal Item
Your personal item — the bag under the seat in front of you — is prime real estate. Pack it with items you need during the flight, not in-destination items.
What belongs in your personal item
Laptop and charger (easiest access during flight). Headphones. Snacks and water bottle. Reading material. Any items you’ll need at security (liquids bag, laptop for the bin). Your wallet and phone. A light layer if not wearing one. The personal item is your in-flight survival kit — pack it so you never need to open the overhead bin once seated.
Best personal item bags
A structured backpack with a laptop sleeve is the most versatile personal item — it fits under the seat, keeps contents organized, and carries comfortably through the airport. Tote bags work but items shift and it’s harder to find things quickly. Crossbody bags are great for smaller personal items when you’re not bringing a laptop. Look for a bag that expands slightly so you can add a layer or snack purchases after security.
At the Gate
Carry-On Tips for Boarding
Board as early as possible to secure overhead bin space
Overhead bin space fills up from front to back, and from larger items to smaller. Board early — use your boarding group, elite status, or travel credit card early boarding benefit. If you board late and there’s no bin space near your seat, ask a flight attendant rather than walking to the back of the plane — they can often find creative solutions.
Place your bag wheels-first in the overhead bin
Put your carry-on in the overhead bin with the wheels going in first and the handle facing out. This fits more bags in the bin and makes it easier for everyone to retrieve their items. Place your personal item under the seat in front of you, not in the overhead bin — overhead space is for carry-ons, under-seat space is for personal items.
What to do if your carry-on gets gate-checked
On full flights or small regional aircraft, gate agents may ask you to check your carry-on at the gate at no charge. Before handing it over, quickly transfer your valuables, medications, electronics, and any items you need for the flight to your personal item. Gate-checked bags are returned at the jet bridge upon arrival — not at baggage claim — so the inconvenience is minimal on direct flights.
See also: How to Pack for an Overnight or Short Trip, How to Pack for a Week-Long Vacation, and How to Pack for a European Vacation.
Disclaimer
TSA rules, airline carry-on size limits, and baggage policies change frequently and vary by airline and aircraft type. Always verify current restrictions with TSA at tsa.gov and your specific airline before travel. Information on this page is for general guidance only.