What's Not Allowed in Carry-On Baggage: Full Guide

Airport security rules exist to prevent weapons and dangerous materials from reaching aircraft cabins. What counts as dangerous is sometimes intuitive (knives, firearms) and sometimes not (gel shoe inserts, certain Christmas novelties, specific battery capacities). This guide covers what's banned, why, and what the rules look like in the US versus the EU.

Sharp Objects

Knives and Blades

Banned in carry-on everywhere:

• All knives with fixed blades, regardless of length
• Folding knives, pocket knives, and multi-tools with blades
• Box cutters and Stanley-type utility knives
• Craft knives (X-Acto / scalpel style)
• Letter openers with pointed or sharp edges
• Swords, machetes, and ceremonial knives

Scissors — country-specific:

• US (TSA): Scissors with blades shorter than 4 inches (10.2 cm) measured from the pivot are allowed
• EU: Scissors with blades over 6 cm are banned; shorter blades allowed
• UK: Scissors with blades over 6 cm are banned
• Australia: All scissors with pointed tips are banned; blunt-tip only

Razors

• Cartridge razors: Allowed everywhere. The blade is encased and not removable without destroying the cartridge.
• Disposable plastic razors: Allowed. The blade is fixed in plastic.
• Safety razor blades (loose): Banned. The blade itself, outside a cartridge, cannot travel in carry-on.
• Safety razor body (without blades): Generally allowed, but the blades must go in checked luggage.
• Straight razors: Banned.

Needles

Sewing needles and knitting needles are allowed in the US, EU, and UK. Syringes are allowed with documented medical need.

Sporting Equipment

All sports equipment that could be used as a striking weapon must go in checked luggage: baseball/cricket bats, golf clubs, hockey and lacrosse sticks, ski poles, snooker cues, bows and arrows, and skateboard decks. Fishing rods are sometimes allowed at security discretion — confirm in advance.

Tools

Tools over 7 inches (17.8 cm) are banned from carry-on under TSA rules. Banned everywhere: power drills, hammers, crowbars, saws, bolt cutters, axes, and chisels. Small screwdrivers, pliers, and wrenches under 7 inches are allowed by TSA. The EU is stricter — any tool that could damage aircraft or injure crew may be banned at officer discretion, regardless of size.

Firearms and Replicas

Completely banned from carry-on: actual firearms, starter pistols, realistic replicas, BB and pellet guns, flare guns, and spear guns. Real firearms may travel in checked baggage only — unloaded, in a hard-sided locked case, declared to the airline at check-in.

Liquids, Gels, and Aerosols

The 100ml / 3.4 fl oz rule applies in the US, EU, UK, Australia, and most countries. Key points:

• Each container must be 100ml or less (the actual volume of liquid inside is irrelevant — a 200ml bottle that is half empty is still banned)
• All containers must fit in a single 1-litre (approximately 1-quart) clear resealable bag
• One such bag per passenger
• Exceptions: baby formula, breast milk, and prescription medications in amounts reasonable for the journey

Gel shoe inserts: Gel or liquid-based insoles (including memory foam gel insoles) are technically subject to liquid rules. At most airports these are overlooked if they are inside worn shoes, but at strict security checkpoints (particularly in the EU and UK post-Brexit) they may be confiscated. If your insoles are gel-based and you need them, wear them inside your shoes through security.

Lithium Batteries

Lithium batteries are banned from checked luggage above certain capacities precisely because they must remain in the cabin where a fire can be observed and suppressed.

Carry-On Rules for Lithium Batteries

Battery type	Carry-on	Checked
Up to 100 Wh (most phones, laptops)	Allowed	Allowed inside device
100–160 Wh (large power banks, some e-bike batteries)	Allowed with airline approval	Banned
Over 160 Wh	Banned	Banned
Spare lithium-ion batteries (loose)	Carry-on only, in battery case	Banned

Power banks specifically: Loose power banks must travel in carry-on. They cannot go in checked luggage. Most travel power banks are under 100 Wh, which is equivalent to roughly 27,000 mAh at 3.7V.

Self-Defense Items

Banned from carry-on everywhere: pepper spray/mace, tasers, stun guns, kubotans, and brass knuckles. In the US, one small pepper spray container (≤118 ml) and tasers are permitted in checked baggage only. Personal alarms that emit a sound are generally allowed.

Explosive and Flammable Items

• Christmas crackers (UK and Australia): Banned from carry-on AND checked bags. The small explosive snap mechanism classifies them as pyrotechnics. This catches many UK travelers by surprise during the holiday season.
• Fireworks, flares, and party poppers: Banned from carry-on and checked baggage
• Lighter fuel: Banned
• One lighter or book of matches: Allowed in carry-on in US; one lighter allowed on person in EU

TSA vs EU Rules: Key Differences

Item	TSA (US)	EU
Scissors	Allowed if blade under 4 inches	Allowed if blade under 6 cm
Small tools	Allowed if under 7 inches	Often banned at discretion
Knitting needles	Allowed	Allowed
Liquids	100ml rule, 1-quart bag	100ml rule, 1-litre bag
Nail clippers	Allowed	Allowed
Gel shoe inserts	Often overlooked	Enforced more strictly
Christmas crackers	Allowed (no rule)	Banned in UK

The EU tends to be more strictly enforced at a procedural level. TSA officer discretion varies significantly by airport.

What to Do When You Realize at Security

If a banned item is in your carry-on at the checkpoint: declare it voluntarily before scanning (officers escalate less when you raise it first), return to check-in if time allows, or surrender it to be confiscated. Some large airports have postal services near the entrance where you can mail items home. Items you genuinely didn't know were banned typically result in confiscation only — no further consequence. If you're ever unsure, check the TSA's "What Can I Bring?" tool or your country's equivalent before packing.