Every year, millions of travelers make the same mistakes at airport security checkpoints. Some are honest slip-ups. Some are jaw-dropping acts of boldness. Either way, the result is the same – delays, confiscations, fines, and in some cases, handcuffs. TSA officers have seen it all, and they want you to know what not to do before you zip up that bag and head to the airport.
The rules are not as complicated as people think, yet the numbers tell a different story. Thousands of prohibited items are flagged every single day across hundreds of U.S. airports. Whether you’re a seasoned traveler or someone who only flies once or twice a year, there’s a decent chance you’ve packed something you weren’t supposed to. Let’s dive in and get this sorted out before your next trip.
1. Firearms and Loaded Guns
This one sounds obvious, but the data is genuinely shocking. In 2024, TSA officers detected 6,678 firearms at checkpoints across 277 airports nationwide. That’s roughly 18 guns per day. What’s even more alarming is the condition they were found in.
Of the guns found in 2024, about 94 percent were loaded, TSA reported. That is not a typo. Loaded. On the way to a security checkpoint. Even if a traveler has a concealed weapons permit, firearms are not permitted in carry-on luggage. A permit means absolutely nothing at the security lane.
In addition to potential criminal citations for bringing a firearm in carry-on luggage, TSA can levy a civil penalty against the traveler of up to $14,950. Firearms can be transported on a commercial aircraft only if they are unloaded, packed in a locked, hard-sided case and placed in checked baggage. So there is a legal path – just not through the carry-on lane.
2. Knives, Box Cutters, and Sharp Objects
Knives and sharp objects are among the prohibited items that get confiscated most often, and seizures of multi-tools, folding pocket knives, scissors, corkscrews, box cutters, and safety razors are all typical. Many people forget a pocketknife is tucked in a jacket pocket or clipped to a bag. Honest mistake, real consequences.
In 2024, officers saw some particularly creative concealment. In March, a passenger at Seattle-Tacoma International Airport was busted attempting to transport a knife concealed inside the shell of their laptop. That’s next-level problem-solving for all the wrong reasons.
Knives of all kinds are a frequent item people try to get past security. The TSA rule is that knives are not allowed in carry-ons but can be packed in checked bags if blades are sheathed or securely wrapped to prevent injury to baggage handlers and inspectors. Simple as that. Just check it.
3. Oversized Liquids, Gels, and Aerosols
Here’s the thing – the 3-1-1 liquid rule has been in place for nearly two decades, and it still catches people off guard constantly. Liquids, aerosols, gels, creams, and pastes exceeding the 3.4-ounce limit are among the most frequently confiscated items. These include everyday products like water bottles, coffee cups, toothpaste, lotions, perfumes, and even duty-free alcohol.
Water in a bottle that weighs more than 3.4 ounces is one of the most surrendered items at security checkpoints, according to a TSA spokesperson. Honestly, I think this is pure reflex for a lot of travelers – you grab your reusable bottle, toss it in the bag, and completely forget it’s still full. It happens to even the most experienced flyers.
The most common items voluntarily surrendered at airport security checkpoints include oversized liquids, oversized gels, oversized aerosols, knives and tools larger than seven inches. The fix? Empty your bottle before security, or buy water once you’re past the checkpoint. It costs a couple of dollars but saves a whole headache.
4. Fireworks and Explosive Devices
It sounds almost unbelievable, but fireworks show up at checkpoints more often than anyone would expect. The traveling public is reminded that fireworks, which are a type of explosive, are never allowed on board an aircraft in carry-on or checked luggage. Not seasonal. Not novelty. Not even sparklers. None of it.
The LAX incident in December 2024 really put this into perspective. The carry-on bag contained a gamut of prohibited items: 82 consumer grade fireworks, three knives, two replica firearms and one canister of pepper spray. That’s not forgetfulness – that’s a whole strategy. TSA and law enforcement were on it immediately.
Replicas and props that look like explosive devices are equally forbidden. Anything that resembles an explosive, whether inert, active, or a replica, is never allowed in carry-on or checked baggage. A fake grenade is treated just like a real one at the checkpoint. Coming in at number two on the best catches of 2024, at the El Paso International Airport, an improvised explosive device was discovered in a passenger’s carry-on bag.
5. Pepper Spray and Mace
Many people carry pepper spray as a daily self-defense item and simply toss it into their travel bag without thinking. Pepper spray and mace are not allowed in carry-on bags. This applies regardless of the size of the canister, regardless of your personal safety concerns, and regardless of whether you have a permit to carry it in your home state.
You can face penalties for attempting to bring prohibited items like pepper spray through an airport security checkpoint. The TSA has the authority to confiscate the item and may issue civil fines, and the final decision on penalties rests with the TSA officer based on the specific situation. So it’s not something you want to test your luck with.
There is a limited option for checked baggage. One 4-ounce container of pepper spray is permitted in checked baggage provided it is equipped with a safety mechanism to prevent accidental discharge. Self-defense sprays containing more than 2 percent by mass of tear gas are prohibited even in checked baggage. Pack it smart or leave it home.
6. Spare Lithium Batteries and Power Banks in Checked Bags
This one is newer and trips up even frequent travelers. The instinct is to throw your power bank in your checked suitcase for safekeeping. That is exactly the wrong move. Portable chargers or power banks containing a lithium-ion battery must be packed in carry-on bags. Spare lithium batteries, which include both power banks and phone chargers, are prohibited in checked luggage.
As of March 1, 2025, TSA rules prohibited passengers from packing portable chargers, power banks, and cellphone battery charging cases that contain lithium-ion batteries in checked luggage. This is a relatively fresh rule update, so don’t assume your old habits still apply.
The reason is fire safety. Loose lithium batteries pose a fire risk if they’re damaged, so they need to be kept in the cabin where the crew can respond quickly in the event of an incident. Anything up to 100Wh is generally permitted without approval, 101 to 160Wh requires airline approval (max two per person), and over 160Wh is typically forbidden unless installed in equipment and given approval.
7. Marijuana and Cannabis Products
Let’s be real – this is a confusing one in 2026, especially with so many U.S. states having legalized recreational cannabis. But state law and federal law are not the same thing at a TSA checkpoint. Federal law classifies marijuana as a Schedule I drug, so flying with THC-containing cannabis products is illegal. This rule applies even if you travel between two states where cannabis is legal.
Since TSA security is under federal jurisdiction, bringing marijuana through a TSA checkpoint could lead to criminal charges. TSA security officers do not search for marijuana or other drugs. If a substance that appears to be marijuana is observed during security screening, TSA will refer the matter to a law enforcement officer.
There is a narrow exception for compliant hemp products. Marijuana and certain cannabis-infused products, including some Cannabidiol (CBD) oil, remain illegal under federal law except for products that contain no more than 0.3 percent THC on a dry weight basis or that are approved by FDA. Know the distinction or leave it behind.
8. Replica Firearms and Toy Guns
It might look harmless to you, but a realistic replica firearm in a carry-on triggers the same response as the real thing. Any type of replica firearm is prohibited in carry-on baggage and must be transported in checked luggage. No exceptions for toys, props, or collector’s items.
The 2024 X-ray catches were wild in this department. A Mississippi man was arrested on October 16, 2024, after TSA officers at Newark Liberty International Airport intercepted disassembled gun parts concealed in a boot and a LEGO box. The TSA officer detected the fully disassembled 9mm firearm in a carry-on bag at a checkpoint in Terminal A. The gun slide, spring and loaded magazine were mixed right in among the plastic LEGO pieces.
TSA officers encounter prohibited items daily at the security checkpoint and each discovery slows down the security screening process for all travelers. Every fake firearm that triggers a bag check creates delays for everyone in line. It is genuinely not worth it for anybody involved.
9. Concealed or Hidden Items of Any Kind
This is perhaps the most important lesson from TSA’s 2024 catch list: modern X-ray technology sees everything. Attempting to hide an item – any item – inside a shoe, wrapped in tape, tucked inside a laptop, or stuffed inside food packaging is not a clever strategy. It is a guarantee of trouble.
At the Asheville, North Carolina airport, a jar of Jif peanut butter was confiscated after it was found to have marijuana inside of it. In February, a passenger at Chicago Midway International Airport attempted to hide a vape pen inside of a toothpaste tube. Officers found it immediately. They always do.
When a TSA officer discovers a prohibited item in carry-on luggage, they offer the traveler the opportunity to place that item in checked luggage, turn it over to a non-traveling family member or friend, or return it to their vehicle if it is parked nearby. The nation’s 50,000 Transportation Security Administration officers flag thousands of prohibited items a day at more than 430 federalized airports. These officers are not guessing – they are trained professionals with powerful equipment. Honesty and preparation will always beat concealment.
Final Takeaway
The most surprising part of all this is just how preventable every single one of these situations is. A quick check of the TSA website, the free myTSA app, or even a 30-second Google search before packing can save you hundreds or thousands of dollars in fines, a missed flight, or worse. Even if an item is generally permitted, it may be subject to additional screening or not allowed through the checkpoint if it triggers an alarm during the screening process, appears to have been tampered with, or poses other security concerns.
The rules exist for a reason. Pressurized cabins, thousands of passengers, and no easy escape route make aircraft uniquely vulnerable environments. Every flagged item at a checkpoint represents someone who either forgot, didn’t know, or hoped they’d get lucky. Two out of three of those are fixable with a little planning.
So before your next trip, spend five minutes with the TSA’s “What Can I Bring?” tool. Your fellow passengers will thank you, the security line will move faster, and you’ll board your flight without a story you’d rather forget. What would you have thought twice about packing? Tell us in the comments.
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