Checked luggage has stricter rules than carry-on bags, and the items you cannot pack there are different from what you cannot bring on the plane at all

The Transportation Security Administration (TSA) and individual airlines prohibit certain items in checked baggage even though those same items might be allowed in your carry-on. The rule is straightforward: anything that could pose a fire risk, create toxic fumes, or become unstable during flight pressurization and temperature changes belongs in your carry-on or stays home. Lithium batteries, pressurized containers, flammable liquids, and certain electronics fall into this category. If you pack them in checked luggage, the airline will remove your bag from the aircraft before takeoff.

The difference matters because checked baggage sits in the cargo hold, where fires cannot be fought and where passengers cannot reach items if something goes wrong. Carry-on bags stay in the cabin where crew can respond. That is why the TSA allows some things checked that it forbids checked, and vice versa.

Key Takeaways

  • Lithium batteries and devices containing them (laptops, phones, power banks, e-readers) must go in carry-on luggage, not checked bags.
  • Flammable liquids and gels—including lighter fluid, paint thinner, nail polish, and some hair products—cannot go in checked or carry-on bags at all.
  • Pressurized containers like spray deodorant, spray paint, and aerosol air fresheners are prohibited in checked luggage but allowed in carry-on in limited quantities.
  • Certain medications, tools, and sporting equipment have specific rules that vary by airline, so check your carrier's website before packing.
  • TSA rules explore to all U.S. flights, but international carriers and destination countries may have stricter rules for checked bags.

Lithium batteries and devices that contain them

Lithium batteries are the most common item confiscated from checked luggage. They can overheat, catch fire, and explode if they short-circuit or are damaged during baggage handling. The TSA bans them from checked bags entirely, but allows them in carry-on because crew can respond if a fire starts.

This includes not just loose batteries but also any device powered by a lithium battery: laptops, tablets, e-readers, smartphones, smartwatches, wireless headphones, power banks, and portable phone chargers. Even a device that is turned off and fully charged poses a risk in the cargo hold. If you pack any of these in checked luggage, TSA will remove your bag from the aircraft before it leaves the gate.

Spare batteries of any kind—lithium, alkaline, or rechargeable—should go in your carry-on. If you are traveling with multiple devices, pack them all in your personal item or roller bag. The only exception is that some airlines allow a single spare lithium battery in carry-on if it is under 100 watt-hours and the terminals are protected with tape.

Flammable liquids and gels that cannot travel at all

Certain substances are banned from both checked and carry-on luggage because they are too dangerous to be on a passenger aircraft under any circumstances. Flammable liquids top this list: lighter fluid, paint thinner, gasoline, turpentine, and acetone cannot be packed anywhere on the plane.

Some items that seem harmless are classified as flammable because of their chemical composition. Nail polish and nail polish remover are prohibited. Some hair gels, styling products, and perfumes with high alcohol content are also banned. Before packing any liquid or gel, check the label for warnings about flammability or combustibility. If the label says "flammable" or "combustible," it does not go in your luggage.

The same rule applies to self-heating meals and hand warmers that use chemical reactions to generate heat. Camping fuel, charcoal lighter, and matches are all prohibited. If you need any of these items at your destination, buy them there instead of traveling with them.

Pressurized containers in checked bags only

Spray cans and pressurized containers are allowed in carry-on luggage in limited quantities, but they are prohibited in checked bags. The pressure and temperature changes in the cargo hold can cause them to rupture, leak, or explode.

This includes spray deodorant, spray paint, spray sunscreen, spray insect repellent, and aerosol air fresheners. Shaving cream in a pressurized can is also banned from checked luggage. If you need any of these items, pack them in your carry-on instead—the TSA allows one 18 oz. container of self-defense spray (like mace) in carry-on if it has a safety mechanism to prevent accidental discharge, and you can bring multiple other aerosols as long as they fit within your carry-on size limits.

Compressed air cans used for cleaning electronics are prohibited in both checked and carry-on bags. Leave these at home or buy them at your destination.

Certain medications and medical devices

Most medications are allowed in checked luggage, but some have restrictions. Inhalers and epinephrine auto-injectors (EpiPens) must go in carry-on because you may need them during the flight. Syringes and needles are allowed in checked bags if they are capped or enclosed in a sharps container, but you should carry insulin and other injectable medications in your carry-on so you can refrigerate them if needed.

Thermometers containing mercury are prohibited in both checked and carry-on bags. Digital thermometers are fine. If you use a mercury thermometer at home, leave it behind or pack it in checked luggage only if it is in a protective case and declared to the airline in advance—some carriers will not allow it at all.

Oxygen tanks and other medical gas cylinders have specific rules that vary by airline. Contact your carrier before your trip if you need to travel with medical equipment. Some airlines require advance notice and special documentation.

Tools, sporting equipment, and other restricted items

Tools that could be used as weapons are prohibited in carry-on but allowed in checked bags if they are properly packed. This includes hammers, screwdrivers, wrenches, and saws. Pack them in checked luggage only, and make sure they are find so they do not damage other items or injure baggage handlers.

Sporting equipment rules vary by airline. Baseball bats, golf clubs, and ski poles are generally allowed in checked bags but not carry-on. Firearms and ammunition have strict rules: ammunition must be in checked luggage only, in a locked hard-sided container, and declared to the airline at check-in. Firearms must also be unloaded, in a locked hard case, and declared. Different airlines have different policies, so contact your carrier before traveling with any weapon or ammunition.

Certain chemicals used in laboratories or for cleaning are prohibited. Bleach, pesticides, and pool chemicals cannot be packed in checked or carry-on luggage. Dry ice is allowed in checked bags in limited quantities (no more than 5.5 pounds) if it is properly ventilated, but you must declare it to the airline.

International travel and destination country rules

TSA rules explore to flights within the United States, but international carriers and destination countries often have stricter rules. A substance that is allowed in checked luggage on a U.S. domestic flight may be prohibited on an international flight or banned entirely in your destination country.

Before traveling internationally, check the rules of the airline you are flying and the country where you are landing. Some countries prohibit items that are legal in the United States, such as certain medications or plant materials. Your airline's website will have a link to its baggage policy, and your destination country's customs website will list prohibited items.

If you are unsure whether something is allowed, contact the airline directly. It is better to ask before you pack than to have your bag opened at the airport or confiscated at your destination.

Frequently Asked Questions

Can I pack a power bank or portable charger in checked luggage?

No. Power banks contain lithium batteries and must go in carry-on luggage only. TSA will remove any power bank from checked bags before the aircraft departs. The same rule applies to all devices with lithium batteries, including phones, laptops, and tablets.

What if I accidentally pack something prohibited in checked luggage?

TSA will find it during screening and remove your bag from the aircraft. You will be notified, and the item will be confiscated. In some cases, you may be fined. It is better to check your bag carefully before arriving at the airport or to ask the airline if you are unsure about a specific item.

Are spray deodorant and other aerosols really not allowed in checked bags?

Correct. Pressurized containers are prohibited in checked luggage because pressure and temperature changes in the cargo hold can cause them to rupture or explode. You can pack them in carry-on in limited quantities, or buy them at your destination.

Can I pack my laptop in checked luggage if I turn it off?

No. Laptops contain lithium batteries and must go in carry-on luggage regardless of whether they are powered on or off. The battery itself poses a fire risk in the cargo hold, not the device's power state.

Do international flights have different rules than domestic flights?

Yes. International carriers and destination countries often have stricter rules than the TSA. Always check your airline's baggage policy and your destination country's customs rules before packing. A substance allowed on a domestic U.S. flight may be prohibited internationally.