Last Updated on March 20, 2021
To become a packing ninja it’s easiest to learn what NOT to pack. It’s a much shorter list than what you can put in your suitcase.
This post deals with the things you can’t bring on a plane in your hand luggage. That’s the carry-on baggage, the personal item bag that you bring into the airplane cabin with you, and anything you might have in your pockets.
If you want to know what things you can’t pack in checked luggage then check this post.
I won’t just give you a list of items prohibited from the plane. I’ll tell you why it’s banned so you can learn how to figure things out on your own.
The TSA is the Transportation Security Administration. It’s their job to keep flights safe from security threats. They are concerned with catching the bad guys.
Once you learn the general principles then you’ll be able to take one look at something and instantly know whether it’s allowed through the security checkpoint at the airport or not.
Okay here are the things that are prohibited from airplanes.
Liquids, Gels, & Aerosols Over 3.4 Ounces (100 ml)
Here’s the big idea, liquids could be used to make explosives. The TSA can’t physically inspect every bottle containing a liquid that is brought on a plane, so instead, to minimize risk, the quantity each passenger is allowed to bring is limited.
You can only bring one quart-sized bag full of liquids and gels.
The TSA often says “If you can squeeze it, smear it, pump it, spread it, spray it, or spill it then it’s considered a liquid”.
This is also the reasoning behind the TSA powders rule. Powders could potentially be used to make explosives. Powders aren’t prohibited in carry-on bags but the TSA wants passengers to remove powders over 12 oz from their luggage and place them in a separate tray at the x-ray machine.
So it’s not that toothpaste or sunscreen is dangerous. It’s that the passenger might not really be carrying toothpaste or sunscreen. That’s why liquids are restricted.
The only exceptions to the liquids rule are medically necessary liquids, breast milk, and liquids for children and babies.
The liquids rule doesn’t only refer to fluids that you can pour.
Anything that’s not solid is treated as a liquid.
This means that some spreadable foods such as peanut butter are not permitted in hand luggage.
Interestingly, a container of a spreadable food must be less than 3.4 oz but if you take that same food out of the container and spread it on bread to make a sandwich then you are allowed to bring it on board.
Similarly, the peanut butter that’s inside Reeses Peanut Butter Cups doesn’t need to be packed inside your toiletries bag, but a jar of peanut butter would need to be.
These are just some of the quirks of the TSA system.
The second main threat that the TSA worry about is weapons.
The only knife you can bring in carry-on luggage is a non-sharp rounded butter knife without a serrated edge. Other knives or sharp objects need to be packed in checked bags, make sure they are securely wrapped to avoid injury to baggage handlers.
And you can’t bring replica weapons or toy weapons in carry-on bags because they’ll just cause alarm and slow down the security process.
Self-defense items are considered to be weapons too so you can’t bring pepper spray on a plane.
But it’s not only explicit weapons that are banned from inside the cabin. Any items that could be effectively used as makeshift weapons are banned too and need to be packed in checked bags.
Sharp Objects Or Bludgeons
The TSA prohbit passengers from bringing almost anything with a blade on to airplanes.
Disposable razors are okay, the thin blades are not deemed to be strong enough to be a threat.
However safety razors, blenders, cork screws, or anything with a blade will not be permitted past the security checkpoint.
Also anything that can be use as a bludgeon won’t be allowed past security.
So baseball bats, hockey sticks, and any large heavy blunt instruments won’t be allowed onboard.
The TSA officer has the discretion to stop you from boarding with any item that you could use to knock someone out.
That’s why Miss Scarlet can’t do the crime in the first class cabin with the candlestick.
Interesting to note, the only Clue (aka Cluedo Board Game) weapons that are TSA approved are the rope and the wrench. But the wrench must be less than 7 inches so it would take a terribly long time to dispatch Mr Boddy.
Scissors With Blades Longer Than 4 Inches
When I said that you can’t bring any blades on a plane, I lied.
You can bring scissors that have blades shorter than 4-inches from the pivot. But don’t expect to bring any really sharp scissors. If you could realistically use the scissors as a weapon then they won’t be permitted through the checkpoint.
Scissors with blades longer than 4 inches from the pivot point must be packed in your checked bag.
Tools Longer Than 7 Inches
Tools are restricted to being shorter than 7 inches so that they can’t be used as a bludgeon.
So you can’t bring a heavy duty flashlight. A wrench needs to be under 7 inches.
You can’t pack a hammer of any size in carry-on luggage.
Power tools are banned from carry-on luggage and should be packed in checked luggage. Fans of the horror movie genre will understand why. Even lightweight power tools could be used as weapons.
It’s best to remove any batteries if possible and bring them in your cabin luggage, but pack the power tool in your checked baggage.
Lithium Batteries Over 160 WH
You can bring power banks and other lithium batteries on to planes in hand luggage.
In fact, because lithium-ion batteries are a fire risk it’s preferable to pack them in carry-on bags instead of checked baggage.
You are not permitted to pack spare loose lithium batteries in checked luggage.
Power banks or portable chargers under 100 watt hours are fine to pack in hand luggage.
If your power bank is over 100 wh you need to check with your airline if it’s allowed in carry on bags.
Flammable Items That Are Not Toiletries
You can bring a small aerosol deodorant on a plane in your carry-on.
The only aerosols that you can bring on planes are toiletries. These are products that are sprayed on the skin.
If it’s a flammable spray that you don’t spray on your skin you won’t be permitted to bring it on a plane.
Apart from toiletries flammable liquids are not allowed on airplanes.
So spray paint, fuel or anything that is classified as flammable and hazardous won’t be allowed into the cabin.
The same goes for fireworks, or gun powder. We don’t want things blowing up inside airplanes.
Makes sense right? These rules are not there to inconvenience you. They are there to keep you safe.
Alcohol Over 70% ABV
This is also why alcoholic beverages over 70% ABV or 140 proof are not permitted in carry-on or checked bags.
Most airlines in the United States don’t have weight limits for carry-on luggage.
However if you are traveling internationally then you might not be able to bring too many things on a plane.
This is especially true in Asia where they have very restrictive weight limits for hand luggage.
So while this rule doesn’t refer to anything specific you can’t bring any item on a plane that won’t fit in your carry-on suitcase or cause your suitcase to go above any airline weight limit.
Check with your airline to see if they have any weight limits for hand luggage.
Aside from TSA security rules, you might need to think about the customs rules if you are flying internationally.
For example, you are usually only permitted to bring a limited amount of cash or valuables into a country when you land.
And countries often have regulations around importing certain foods, plants or seeds.
Check the customs rules for your destination country if you think you might be flying with “anything to declare”.
The Law Is The Law
The TSA are only responsible for aviation security.
The regular federal laws still apply when you are in the air.
Items that are illegal to possess on the ground are also illegal to possess in the air.
If you are flying internationally make sure you don’t break any laws of your destination country.
There are some countries where even your sex toy could land you in trouble with the local law.
Ask The TSA
If you are still unsure you can use the @AskTSA service on Twitter to ask a question about your item
The TSA will get back to you quickly with an answer.
The Bottom Line
You can’t bring liquids, gels, and aerosols in large quantities onto planes and you can’t bring weapons or items that could be used as weapons.
That covers 90% of the things you can’t bring on to airplanes.
Sometimes you’ll smart ass passengers saying “it’s all security theater”. They suggest that the purpose of these rules and the is to make passengers feels safer about flying but that they don’t really make the skies safer.
Perhaps there is an element of theater at work. But I’d suggest that it’s to make the bad guys think they’ll get caught rather than to trick the passengers into feeling safe.
I know it can be a pain going through airport security but now that you know exactly what can’t be taken on a plane and why then I hope you’ll find packing and the security process a little easier.