What not to pack in your carry-on

Most carry-on delays at security come from a handful of predictable categories — not exotic items, just things packed out of habit. Here's what actually gets a bag pulled aside.

Liquids over 3.4 oz (100 ml)

The 3-1-1 rule: each container must be 3.4 oz or smaller, and all of them together must fit in one clear, quart-size bag per passenger. This catches more people than any other rule, and it applies to anything liquid, gel, or paste — including hair product, sunscreen, peanut butter, and snow globes (yes, really, since they contain liquid). Medications and baby formula are exempt in reasonable quantities, but declare them at the checkpoint.

Sharp objects and tools

Knives, box cutters, axes, and screwdrivers or drill bits longer than 7 inches all have to go in checked luggage. Tweezers, safety (disposable) razors, scissors, and knitting needles are fine in a carry-on — it's blade length and rigidity that matters, not the category of object.

Sporting goods and equipment

Baseball bats, hockey and lacrosse sticks, ski/hiking poles, and golf clubs are all checked-bag only. If you're traveling with sports gear, plan for a second checked bag rather than assuming it'll fit in the cabin.

Anything that could pass as a weapon

Beyond obvious weapons, this includes stun guns, self-defense sprays, brass knuckles, and — at the security officer's discretion — realistic toy weapons or replica explosives. When in doubt, check it or leave it home; contesting a confiscation at the checkpoint rarely goes anywhere.

Lithium batteries: the opposite rule

This one surprises people because it runs backward: spare lithium batteries and power banks are required in carry-on baggage, not allowed in checked bags, because of fire risk in the cargo hold. Most airlines cap an individual power bank around 100Wh without prior approval — check your specific airline if you're traveling with a large one.

Bottom line

Pack liquids in a clear quart bag, sharp and rigid tools in your checked bag, and keep batteries and power banks in the cabin with you. Once your carry-on is sorted, use our packing list generator to build the rest of the list, and our carry-on checker to confirm the bag itself fits your airline.

Sources

• The Points Guy — What Not to Pack in Your Carry-On
• TSA's published prohibited-items list — rules can change; confirm current guidance on tsa.gov before flying, especially internationally where rules vary by country.