What You Can't Bring on a Plane: The Complete Prohibited Items List

Airport security is the only place on earth where a jar of peanut butter is a liquid, a cast-iron skillet is fine, and a perfectly harmless snow globe can end its journey in a bin. The rules aren't arbitrary — they come from the international dangerous-goods framework — but they are counterintuitive, and the pattern that trips up most travelers is this one:

The things you assume go in your carry-on often have to be checked. The things you assume go in your checked bag often have to be in the cabin.

Batteries are the classic reversal. A spare power bank is banned from the hold and welcome in the cabin, because a fire at seat 24C gets noticed and a fire in the cargo hold does not.

Here is the complete practical list, category by category, with the carry-on vs checked call for each — plus the strangest things that have genuinely turned up at a checkpoint.

A note on jurisdiction before we start. Two layers of rules apply to everything below. The global layer is the ICAO Technical Instructions and the IATA Dangerous Goods Regulations, which every commercial airline follows; that's where the battery limits, the flammables bans and the aerosol rules come from, and they're broadly the same worldwide. The local layer is the security screening authority — the TSA in the United States, the relevant national authority elsewhere — and that layer varies. Where a rule below is US-specific, it is labeled. Where a limit varies, it says "typically." Your airline can always be stricter than the regulator, and the final call at the checkpoint always belongs to the officer standing in front of you. For carrier-specific policies, check the airline's own guide — for example American Airlines or British Airways — or browse all airline guides.

Liquids, Gels, Aerosols and Pastes

The 3-1-1 rule (and its metric twin)

The core rule is near-universal, even if the marketing name isn't:

Each container: 100 ml / 3.4 oz maximum
All containers together: fit inside one transparent resealable bag of roughly one liter
One such bag per passenger

The US calls this "3-1-1" (3.4 ounces, 1 bag, 1 passenger). Most of the rest of the world calls it the 100 ml rule. Same rule.

The container size is what matters, not how full it is. A half-empty 200 ml bottle of shampoo is still a 200 ml container, and it still fails. Officers do not have time to negotiate about headspace.

What counts as a "liquid"

Far more than you think. A liquid, for screening purposes, is anything that doesn't hold its shape:

Water, drinks, soup, syrup
Toothpaste, hair gel, hand sanitizer, sunscreen
Peanut butter, hummus, yogurt, jam, honey, soft cheese
Mascara, liquid foundation, lip gloss
Aerosol deodorant and shaving foam
Snow globes — the classic, because the liquid volume is usually unknowable and usually over 100 ml

Exceptions above 100 ml

Allowed in "reasonable quantities" above the limit, but declare them at the checkpoint and expect separate screening:

Baby formula, breast milk, baby food and juice for an infant traveling with you
Prescription and essential over-the-counter medications (liquid or gel); bring the pharmacy labeling or a prescription copy for anything unusual
Ice packs and gel packs needed to keep the above cool

Duty-free liquids bought airside are allowed above 100 ml if they're sealed in a tamper-evident security bag with the receipt visible inside. Keep the bag sealed until final destination — opening it at a connecting airport typically resets you to the 100 ml rule and the bottle is lost. This bites travelers at connections constantly.

Checked bags: no volume limit on ordinary toiletries. Alcohol is limited — typically nothing over 70% ABV at all, and beverages between 24% and 70% ABV capped around 5 liters per passenger in retail packaging. Under 24% ABV is generally unrestricted by dangerous-goods rules, though customs allowances still apply at your destination.

Item	Carry-on	Checked
Toiletries ≤100 ml in the bag	Yes	Yes
Toiletries >100 ml	No	Yes
Baby formula / breast milk	Yes, declare	Yes
Liquid medication	Yes, declare	Yes
Duty-free in sealed STEB	Yes	Yes
Spirits over 70% ABV	No	No

Sharp Objects

The general principle: if it has an edge or a point and it's longer than a finger, it belongs in the hold.

Not allowed in the cabin — pack in checked baggage:

Knives of any kind, including hunting, hobby, utility and ceramic blades
Box cutters, razor blades not in a cartridge, and straight razors
Scissors with blades longer than roughly 6 cm / 4 inches from the pivot (the exact threshold varies by country — some measure from the pivot, some from the handle)
Ice axes, ice picks, meat cleavers, sabres and swords
Darts, throwing stars, arrows and bolts
Corkscrews with an integrated blade (the "waiter's friend" foil cutter)

Usually fine in the cabin:

Disposable and cartridge razors (the blade is enclosed)
Nail clippers, tweezers, eyebrow scissors
Small scissors under the length threshold
Knitting and crochet needles — generally permitted, but this one genuinely varies by country, so a screener's refusal is not a mistake
Blunt-nosed safety scissors

Packing tip: anything sharp going into checked baggage must be sheathed or securely wrapped. That isn't a formality — baggage handlers open damaged bags by hand, and an unsheathed cleaver in a burst suitcase is exactly the injury the rule exists to prevent.

Tools

The dividing line is length, and the usual threshold is 7 inches / about 18 cm.

Cabin-allowed: screwdrivers, wrenches, pliers, spanners and Allen keys under the threshold. Multi-tools only if they contain no blade — a bladed multi-tool is a knife with accessories, and it will be treated as one.

Checked only, regardless of length:

Drills and drill bits
Saws, including hacksaws and handsaws
Hammers, mallets, crowbars, pry bars
Bolt cutters and axes
Nail guns and other powder-actuated tools
Cordless tools with removable batteries — the tool goes in the hold, but see the battery section, because the battery may not

Cabin crew know their own tools. The point of the length limit is leverage and reach, not sharpness, which is why a long screwdriver is a problem and a short one isn't.

Sporting Goods

Mostly a "checked, and probably at extra cost" category. Anything that works as a club, bat or projectile is a club, bat or projectile.

Checked only:

Baseball and cricket bats, golf clubs, hockey and lacrosse sticks
Pool cues and ski poles
Bows, crossbows and arrows
Spearguns and dive knives
Bowling pins — yes, specifically; they're weighted clubs
Martial arts weapons: nunchaku, kubaton, batons, brass knuckles
Baseballs and cricket balls are fine either way, but a bag of them draws a second look

Cabin-allowed: tennis, badminton and squash rackets in most jurisdictions (check the airline — several restrict them regardless), climbing helmets, and foam or inflatable sporting toys.

Scuba tanks are a special case: allowed only if the valve is removed so the cylinder is demonstrably empty and open to inspection. A sealed tank is a pressure vessel and is refused.

Compressed-gas dive computers, bicycles and surfboards are permitted as checked baggage but almost always attract oversize fees. Consult your airline's baggage table before you get to the counter.

Firearms, Ammunition and Replicas

Never in the cabin. Anywhere. There is no version of this that works.

Checked carriage is possible on most airlines, and it is a formal process:

Declare the firearm at check-in, every time, without exception
Unloaded, in a locked hard-sided case that only you can open
Ammunition in the manufacturer's original packaging or an equivalent purpose-made box, usually capped around 5 kg / 11 lb per passenger
Magazines emptied and packed to protect the primers
Firearm parts — including scopes, bolts and receivers — follow the same rule as the firearm

Replicas and toys count. Realistic imitation firearms, cap guns, airsoft guns, BB guns, paintball markers, starter pistols and 3D-printed models are all treated as the real thing at the checkpoint and must be checked. So is anything resembling an explosive device, including inert training aids, novelty grenades and film props. "It's obviously fake" is an argument you will lose, and in some countries lose expensively.

Carriage of firearms is also a legal question, not just a baggage question. Permits and destination law govern whether you may possess it on arrival at all. Check the destination country's rules well before you fly.

Self-Defense Items

The category with the widest country-to-country variation, and the one most likely to be confiscated by a traveler who genuinely believed they were fine.

Item	Carry-on	Checked
Pepper spray / mace	No	Sometimes — US: one 118 ml container with a safety cap, max 2% CS/CN; banned outright in many countries
Stun guns / tasers	No	Sometimes, batteries removed; illegal in many countries
Brass knuckles	No	Yes
Batons, telescopic and fixed	No	Yes
Personal alarms (sound only)	Yes	Yes
Tactical pens with a spike	No	Yes

Pepper spray is worth a paragraph of its own because the rules are so inconsistent. Many countries prohibit civilian possession entirely, which means a canister that was legal to check on the outbound leg can be a criminal matter on arrival. If you're crossing a border with one, check both ends first, and when in doubt, buy at destination or don't travel with it.

Lithium Batteries and Electronics

This is the category that runs backwards, and it's the one worth reading twice. Lithium batteries can enter thermal runaway; a fire in the cabin gets a crew member with a halon extinguisher and a containment bag within seconds, and a fire in the hold does not. So the safe place is the cabin, and the rules enforce that.

Spare batteries and power banks

Cabin only. Never in checked baggage. This applies to every loose lithium cell: power banks, camera batteries, drone batteries, laptop spares, e-bike batteries, vape batteries. Terminals must be protected — original packaging, a plastic case, or tape over the contacts. A loose power bank rattling around against keys and coins is exactly the short-circuit scenario the rule targets.

Capacity limits under the IATA framework:

Under 100 Wh — carried freely, no approval needed. This covers nearly all phone, laptop, camera and consumer power banks
100–160 Wh — airline approval required, and typically a maximum of two spares per passenger. Pro camera batteries and larger power banks live here
Over 160 Wh — prohibited as passenger baggage entirely. Ship it as cargo

If your power bank prints only mAh, convert: Wh = (mAh ÷ 1000) × voltage, where lithium-ion cells are nominally 3.7 V. A 20,000 mAh bank is 20 × 3.7 = 74 Wh, comfortably under. A 27,000 mAh bank is about 100 Wh and sits right on the approval boundary. A bank with no printed capacity at all may be refused on principle — screeners cannot approve what they cannot verify.

A live and tightening area: many carriers, particularly in Asia, now also prohibit using or charging power banks in flight and require them to be visible rather than in the overhead bin. Several have adopted this since 2025. Check your airline's current policy — this is the fastest-moving rule on this page.

Devices with batteries installed

Phones, laptops, tablets, cameras and e-readers may go in either bag. In the cabin is strongly preferred, and if a device does go in the hold it must be completely powered off (not sleeping), protected from accidental activation, and packed so it can't be crushed.

E-cigarettes and vapes

Cabin only, and never used in flight. Vaping onboard is prohibited everywhere and treated as seriously as smoking. Devices must be carried on the person or in cabin baggage, protected against accidental activation, and never charged onboard.

Smart luggage

Suitcases with built-in lithium batteries are permitted only if the battery is removable. If you check the bag, remove the battery and carry it in the cabin. If the battery is non-removable, most airlines will refuse the bag entirely. Several carriers name this restriction explicitly in their conditions of carriage.

Other electronics

Hoverboards, e-scooters, e-skateboards and self-balancing boards: banned by most airlines in both cabin and hold — the batteries are large and the quality is inconsistent
Medical devices with lithium batteries (CPAP, portable oxygen concentrators, mobility scooters) have their own accommodation rules — notify the airline in advance, generally 48 hours
Laptops in checked bags are permitted but discouraged, and are effectively banned by some carriers

Flammables and Aerosols

Straightforward, and near-universally banned in both bags:

Petrol, lighter fluid, camping fuel, paint thinner, turpentine
Fireworks, flares, sparklers, party poppers and Christmas crackers
Strike-anywhere matches
Butane, propane and camping-stove canisters — empty or not
Lighter refills
Aerosol paint and industrial aerosols

Lighters and matches have an odd carve-out: typically one ordinary lighter or one book of safety matches, carried on your person — not in your carry-on bag, not in the hold. Torch and jet lighters are usually banned outright, as are lighters containing unabsorbed liquid fuel.

Personal-care aerosols (deodorant, hairspray, dry shampoo) are allowed: under 100 ml in the cabin liquids bag, and in checked baggage up to typically 0.5 kg or 0.5 L per container and 2 kg or 2 L in total, with the cap fitted or the valve otherwise protected.

Camping stoves may be checked only if the fuel container is completely empty and has been aired out long enough that no vapor remains. Screeners will smell it. They are extremely good at this.

Chemicals and Toxic Substances

Banned in both cabin and checked baggage:

Bleach, drain cleaner, industrial solvents, wet-cell (spillable) batteries
Pool chemicals, chlorine, pesticides, insecticides, fertilizer
Mercury thermometers and mercury barometers (a small medical mercury thermometer in a protective case is a narrow exception on some carriers)
Tear gas and other incapacitating agents
Poisons and infectious substances

Allowed with limits: small quantities of non-flammable, non-toxic toiletries and medicinal items — typically up to 0.5 kg or 0.5 L per container and 2 kg or 2 L total per passenger, in both bags.

Dry ice for perishables is permitted up to about 2.5 kg per passenger if the package vents CO₂ and is marked "Dry ice" with the net weight and contents. Airline approval is required, and this is one to arrange before you arrive at the airport rather than at the counter.

Magnetized and Radioactive Materials

Two categories that almost nobody thinks about until they're carrying something unusual.

Strong magnets — the kind in loudspeakers, MRI components, industrial motors and large neodymium sets — are restricted because they can deflect aircraft compasses. The regulatory test is field strength at a set distance from the package. Consumer-scale magnets in headphones and speakers are fine; a box of large neodymium magnets requires airline clearance and may need to travel as declared cargo.

Radioactive material is prohibited outright, with a narrow exception: a person who has undergone a medical procedure involving radiopharmaceuticals may fly, though the residual activity can set off detectors. Carry the treating physician's documentation — it saves a long conversation.

Smoke detectors containing americium and certain measuring instruments also fall under this heading and generally require airline approval.

Powders

A newer rule than most, and one that catches people out on US-bound flights.

US-specific: powder-like substances over 12 oz / 350 ml in carry-on baggage receive additional screening, and may be prohibited from the cabin outright if they can't be resolved at the checkpoint. This includes protein powder, ground coffee, spices, baby powder, cosmetics and — the awkward one — cremated remains.

Several other countries apply a comparable rule on flights inbound to the US. Elsewhere, powders are generally unrestricted.

Cremated remains deserve their own note. Many authorities require the urn to be made of a material that screeners can see through on X-ray — wood, plastic or cardboard rather than lead-lined stone or thick metal — because the container cannot be opened for inspection under any circumstances. Carry the death certificate and the crematorium documentation, and consider a temporary screening-friendly container for the flight. Some airlines require the remains to travel as cabin baggage; others require them checked. This is one to call about.

Food, Plants and Agricultural Items

Security will usually let food through — customs is the checkpoint that matters. Solid food is fine in either bag; spreadable food obeys the liquids rule. Bringing meat, dairy, fresh produce, seeds or plants across a border is a biosecurity question governed by the destination country, and the penalties in places like Australia and New Zealand are substantial. Declare, always. It is free to declare and expensive not to.

Sidebar: The Weirdest Things Actually Confiscated

Every category above exists because of a real risk. These are the items where the rule is real, correct, and still very funny.

Snow globes. The most confiscated souvenir in aviation. The liquid volume is usually unmeasurable, usually over 100 ml, and always heartbreaking. Buy them at your destination and check them.

Peanut butter. Reliably confiscated, reliably disputed. It spreads, therefore it flows, therefore it's a liquid. Same for hummus, Nutella and cranberry sauce — US checkpoints see a genuine spike in disputed cranberry sauce every November.

Cast-iron skillets. Perfectly legal in checked baggage and a favorite piece of security folklore. In the cabin, a heavy pan is a blunt instrument. In the hold, it's cookware. Nothing about the pan changed.

Foam swords and toy weapons. Realistic replicas are refused regardless of material. A foam sword from a theme park is soft, harmless, and still a sword to a screener working a fixed rule. Check it.

Bowling pins. Explicitly named as prohibited in the cabin. They are clubs. Correct call, deeply funny listing.

Frozen water. Ice is not a liquid while it's solid. Completely frozen ice packs typically pass; slushy ones are a liquid and don't. Screening is a sublimation puzzle in ways nobody intended.

The ones you can look up: security agencies post their genuinely extraordinary finds — the chainsaws, the cannonballs, the swords in walking sticks. The TSA's own Instagram account has become an unlikely institution for exactly this reason.

Sidebar: Surprisingly Allowed

Things travelers assume are banned that mostly aren't:

Antlers. Explicitly permitted by the TSA in both cabin and checked baggage, subject to size and to the airline agreeing. The mental image of a passenger boarding with antlers is entirely legitimate.
Artificial skeletons and anatomical models. Allowed. Screening them is memorable for everyone involved.
Live fish in water. Permitted in carry-on in a clear, sealed, transparent container subject to inspection. The water is not counted against the liquids rule.
Fresh whole lobsters. Allowed in a clear, sealed, spill-proof container.
Bicycle chains, prosthetics, harmonicas, bowling balls (the ball, not the pins), and unopened parachutes — all fine, though a parachute must be screened in your presence.
Musical instruments. Allowed in the cabin if they fit the sizer; many airlines have a formal instrument policy, and some allow a purchased seat for a cello. Check the airline's guide.
Knitting needles. Permitted in most jurisdictions, contrary to widespread belief — though not all, so pack a stamped envelope if the project is precious.

Practical Packing Strategy

A rule of thumb that resolves most cases without looking anything up:

Anything that stores energy — batteries, fuel, pressure — goes in the cabin or nowhere. A fire needs to be reachable.
Anything with an edge, a point, or a swing — knives, tools, bats — goes in the hold. A weapon needs to be unreachable.
Anything that pours obeys the 100 ml rule. Including the things you don't think of as pouring.
Anything that looks like a weapon is a weapon at the checkpoint, regardless of what it's made of.
When you genuinely don't know, check the bag rather than the carry-on — unless it's a battery, in which case do the exact opposite.

Give yourself extra time if you're carrying anything on this page that requires a declaration: medication over 100 ml, a firearm, dry ice, large batteries, or remains. Declaring takes two minutes at the counter and can take an hour at the gate.

Before You Fly

Check your airline's specific policy — carriers may be stricter than the regulator, and the battery rules in particular are changing fast. Start with the airline guides.
Check the destination country's import rules for anything unusual, especially self-defense items, food and plants. The country guides are a starting point.
Check the departure airport's security guidance if you're carrying something awkward — some airports have their own procedures for oversize and specialty items. Find yours in the airport directory.
If a rule below matters to your trip, verify it with the airline within a few days of departure. Everything here was accurate as written, and aviation regulations do not stand still.

This guide covers general international practice under the ICAO/IATA dangerous-goods framework plus TSA specifics where labeled. It is not legal advice and it is not a substitute for your airline's conditions of carriage. The screening officer at your checkpoint has the final say — and they have seen the peanut butter argument before.

🚫What You Can't Bring on a Plane: The Complete Prohibited Items List