How to Pack Carry-on Bag for Air Travel? | TSA Rules Made Simple

Packing a carry-on bag the right way comes down to one question: what stays with you in the cabin, and what goes below? The TSA and FAA set the ground rules, and airlines add their own size limits on top. Get these basics right and you’ll sail through security without a repack at the checkpoint.

What Belongs in Your Carry-On

Your carry-on should hold anything you might need during the flight, items too valuable or fragile to risk in checked luggage, and anything you’re legally required to keep with you. The FAA explicitly warns that heavy items belong under the seat in front of you rather than in the overhead bin — a bag falling from above can seriously injure a passenger.

Medications, travel documents, jewelry, laptops, cameras, and a change of clothes all belong in the cabin. Lithium battery-powered devices like power banks, vapes, cell phones, and laptops must fly with you in the cabin; they’re not allowed in checked bags at all.

The TSA 3-1-1 Liquids Rule

The single most common carry-on mistake is misunderstanding how the liquids rule works. TSA’s 3-1-1 rule allows containers of 3.4 ounces (100 milliliters) or less, all placed in one quart-size clear plastic zip-top bag, with one bag per passenger. Toothpaste, shampoo, conditioner, mouthwash, and lotion all fall under this rule.

Here’s the catch most travelers miss: the rule applies to the container size, not what’s left inside it. A half-empty 6-ounce bottle of shampoo still gets confiscated because the bottle itself exceeds 3.4 ounces. Pack travel-sized containers and you’ll never face this problem.

Place your quart-size liquids bag in the front pocket of your carry-on so it’s easy to pull out at the security checkpoint. Nothing slows down a security line faster than digging through a packed bag for liquids.

Carry-On Size and Airline Rules

Your personal item, typically a backpack or purse, must fit under the seat in front of you. But here’s the part travelers forget: airlines set their own stricter limits, and they vary by carrier.

Always check your specific airline’s bag dimensions before you pack. A bag that fits on one carrier’s overhead bins may be too large for another’s, and gate-checking an oversized bag costs time and sometimes money. FAA guidance is clear: verify airline rules before packing.

• Heavy items go under the seat in front of you, never overhead
• Tuck in all bag straps so they don’t catch or dangle
• Don’t stack items on top of other bags in the overhead bin
• Leave carry-ons on the plane during an emergency evacuation

Packing Step by Step

Start with an empty bag and confirm nothing prohibited was left inside from a previous trip. Then decide what goes in your carry-on versus checked luggage before you start packing. Sort liquids, gels, and aerosols into your single quart-size zip-top bag, ensuring it closes completely.

Keep your liquids bag accessible, and place heavier items toward the bottom near the wheels (or toward your back if it’s a backpack). Structure matters: roll clothes to save space and keep heavier items low so the bag rests comfortably in the overhead bin or under the seat.

If you’re ever asked to gate-check your bag at the last minute, remove spare batteries and lithium battery-powered devices first. Those items must stay in the cabin with you, not go into the cargo hold. If you’re in the market for a new bag that meets modern airline size limits, our roundup of the best carry-on travel bag options covers tested picks that fit overhead bins on major U.S. carriers.

One more safety note from the FAA: if an emergency evacuation happens, leave your carry-on on the plane. Grabbing a bag slows everyone down and puts lives at risk.