If you’re flying within the USA, and you own a firearm, there is a solution to provide some extra security.

As Deviant Ollam explains, if you have a firearm in your checked luggage, you need to have it in a hardcase, locked with a non-TSA lock. The idea is likely having a small handgun case in a larger bag, but nothing precludes you from having a large case as your checked luggage, that just happens to have your gun in it.

You need to declare your firearm when checking your luggage, fill in a form, show your firearm to be unloaded, have your luggage screened while you’re present, then lock it. And that’s it. You have to keep the keys to that lock on your person.

As Deviant explains, even a starter pistol counts as a firearm for the TSA.
On Deviant’s site you can read many accounts of people who have flown like this.

A lot of good answers on here about your bag being unlikely to be stolen, but I wanted to address this part

I very much fear losing my stuff. I would be stranded with only what I have on me. It would be just like in the 1970 book "Metropole". Shudder…

In most major countries, when you check in your bag, the airline has a "duty of care" to deliver it safely back to you afterwards. If your bag is lost, they are required to compensate you (within general limits) See for example US Dept of Transport guidelines & General Baggage Help

Even if the bag is just delayed (from the DOT reference above)

Airlines are required to compensate passengers for reasonable, verifiable, and actual incidental expenses that they may incur while their bags are delayed – subject to the maximum liability limits.

That means you can immediately buy necessary clothing and toiletries while you wait for them to deliver a delayed bag, or if they declare the bag lost.

I had this happen years ago in Phoenix. I went out and bought light trousers & a top because my travel clothes were not suitable for Arizona in summer and they reimbursed me for the expenses when I showed the receipts

As the other answers state, it is better to have a few necessities & anything valuable in hand luggage, but do not worry too much about losing clothes or being stranded with very few items.

In 2012, I funded a Kickstarter for coin-sized Bluetooth tags that will give proximity alerts and (croudsourced) tracking. I got those for my luggage in a trip planned for 2013.

Now, that technology is even better and commonplace; it’s even built into some objects like my headphones and even Apple is selling "tags" now.

Put a tracking tag in each bag and you won’t have to wait right at the belt, but can be alerted on your phone when the bag is in range, and can follow it if someone else takes it, detect that it’s in the baggage-claim locker if it arrived without you, etc.

You can even get trackers that are built using the chips used for phones and tablets, that take a USIM card and has GPS, so will report its position as it travels. You can buy a cheap "feature phone" for $20 and just use it for that purpose.

How do you all solve this problem?

Simple:

I tend to abstain from flaunting my Rolex collection at the check-in counter and placing it in my luggage before the agent applies the tag to my handle.

Also, when sitting next to someone on the plane I abstain from talking about the Rolex collection in my checked luggage which is colored bright purple with conspicuous unicorn decals.

In all seriousness:

It’s a non-issue.

Nobody is interested in your bottle of shampoo that was too big to carry on and presumably dirty underwear.

In good conscience everyone is trying to find their own luggage and move on with their journey.

As a former ticket agent I’ve seen it all:

• People grab and leave with wrong luggage but later return with humility: 3 times in 4 years
• Luggage lost in the Atlanta’s connection abyss: 5 times in 4 years
• Luggage delayed but delivered same day: too many to count
• Luggage delayed and delivered after 1 or more days later: frequent
• Luggage flat out stolen: if the thief is good then it might have been counted in my Atlanta stat =)

Bottom line:

Don’t put anything in your checked luggage that you are unable to function without or cannot easily replace for the duration of your travels.

You usually have the possibility of stowing small luggage items underneath the seat in front, where you (and only you) can reach them. No, the person in front does not have access to that area.

So what I do is put everything precious that I can’t live without in the pockets of my coat, and in a small briefcase-sized travel bag which is sturdy and reliable. Hence my cards, my smartphone and (when travelling on business) my laptop are all directly under my feet and nobody can get them.

As far as the big luggage is concerned, I make sure I don’t travel with anything irreplaceable. If you lose your clothes and toiletries, purchase them at the other end and your insurance should cover the cost (although I have never tried that, so I am only assuming here).

When you get to the carousel, position yourself as close as possible to the chute outlet. I always do this. It is always possible to position yourself so as to directly see every single piece come trundling out. Hence you are very unlikely to lose your baggage to some random chancer grabbing someone else’s suitcase for whatever reason.

When you go through security on the way to embarking, you will have to unpack your personal hand-held baggage to some extent (empty your pockets, put your laptop in a separate tray) so it can be sent through the security screening. You then have to reclaim your belongings after you have passed through the metal detector, but it is usually the case that you get through first. On the offchance that you do find your hand-held goes through the screen before you, and someone has made off with it, your recourse would be to alert the security people urgently that this has happened — but I have never known it to happen, and I doubt it is a common thing.

Carry very expensive/important items on your body (money, passports, smarthphone, tickets etc.).

The next most important things go with you on the plane in a rucksack. On some flights, you have to put it in overhead storage; on other flights, you may be able to store it between your legs or under your seat or the seat in front of you. The stewardesses will let you know. As everybody is very much confined to their seat and very visible to everybody, those items can be considered safe. If you have to go to the airplane toilet, be sensible; i.e. I would not leave my phone lying around back at my seat, but I would let my laptop behind, no problem.

For your main luggage, which goes into the airplane on its own, make it easily visible and distinguishable. On one of my international flights, I used a cheap flight case from a walmart equivalent in my country. Needlessly to say, when waiting for my stuff, there were several of exactly the same bag on display. Since then, I have a big smiley or other marker something on my luggage – I see it from afar, and have zero risk of taking someone else’s stuff.

Aside from all of that, relax. Be early at the airport, give yourself time, enjoy the ride.

Security Cameras + Identification = bad idea to steal from baggage claim

Virtually all airports have the baggage claim only accessible for passengers and have a fair number of cameras in the baggage claim area. Combine this with the fact that all passengers have to go through some ID check (also with cameras) and it means that any person in the baggage claim area can be visually identified.

Most of the expensive stuff is not in checked luggage = bad idea to steal from baggage claim

Most people do not put expensive jewelry or similar items in their checked luggage. This means that the chance of getting something valuable for a thief are very low.

Conclusion

Get a cheap (or even better old), clearly identifiable bag and you should be fine. The chance of your bag being stolen is far higher before you enter an airport and after you leave it. The trick with travel is mostly about not making yourself look attractive for thieves. Don’t use TSA locks (they don’t stop anybody and make your bag look more expensive), don’t walk around with an iPhone + Apple Watch, don’t wear fancy jewelry, etc.

Straps
Other answers have touched upon recommendations I’d do myself: put valuables in in your carry-ons and be prepared to not get your checked-in luggage (even though it is an extremely low probability). Having colored strings or even straps that completely surround the luggage could help. You could even write on or print on a nylon strap your name or some other blatantly obvious identifier.

Insurance
Another option that doesn’t answer your question directly but may assuage your fear is travel insurance. This way you can replace your late or lost luggage.

Bag management
Another consideration to avoid robbery is to not leave your most valuable objects alone if you go to the airplane bathroom. Or at least have a plan. I feel a bit ambivalent about bringing stuff to the airplane bathroom, because I don’t want to bring a whole backpack with my laptop and whatever into the airplane bathroom. I feel weird about it; I don’t want to make other passengers nervous, if that makes sense (this may be a ‘me’ thing; I wonder what others on this site think).

So what I’ve come to do is to have multiple ‘mini bags’. I have a hidden ultra-thin fanny pack that is hidden underneath my clothes, in which I store some money, my passports, and a boarding pass (although these last ones have been replaced by digital phone-based passes in the last few trips I’ve taken…).

I also have a travel toiletries bag, which is just a big zip-loc. This bag exists in case I have an absurdly long flight or layover, or in case my luggage never makes it home (insurance notwithstanding).

Finally, I have a bag inside of my backpack. It’s a bag made only of cloth, so that it can fold and not take space. I usually use it in airports to leave my heavy backpack stationed with a trusted friend, while I wander around the airport in search for food or a bathroom. But I could put stuff in it and take it to the airplane bathroom with me, leaving my backpack under the seat in front of me in the meantime.

However, what I actually do when I go to the bathroom (and this is the "plan" that I mentioned earlier), is, once I’m back, check that my computer, my camera, and my headphones are still there.

Hopefully this helps 🙂

Another approach is a multi-tier approach. Never put anything in check-in luggage you cannot live without and never anything of value (electronic devices, cash don’t put it).

Then in your hand-luggage you put everything you need for one day (in case your suitcase gets delayed you usually receive it a day after, or you get cash from the airline to purchase new stuff), so being able to freshen up after the flight is really good.

Also put your electronics in your handluggage. If the hand luggage is very small you can put in under the seat in front of you (almost impossible to steal from there). If you bring a laptop, put it in a laptop bag under the seat in front of you and the hand luggage in the overhead compartment.

Now, your passport and cash and creditcard always stays on your body. You can get (sometimes can buy at airport) a ‘pouch’ you can hang around your neck under your clothing where you can put thin precious objects.
(not a big, so called fanny pack). So something like this: https://www.amazon.com/Passport-Holder-Blocking-Travel-Wallet/dp/B01MD19VH3/ref=sr_1_6?dchild=1&keywords=chest+pouch+wolfskin&qid=1625125848&sr=8-6
If you are really paranoid, you get it in skin tone-color, so a street mugger you encounter later after the flight doesn’t see it through your shirt.

Then also carry a wallet with some cash and another credit card.

Carry the on your body items really on your body. I saw once at an overnight flight how another passenger tried to go through the jacket of another passenger from the seat behind.

Yes, this all may sound a bit overcautious, but the key is: do not worry and you do not have to worry if you do it like this; so you can enjoy the flight.

Airlines have very specific rules for "carry-on" bags: bags which you bring onto the airplane when you board. Look them up.

Typically they allow two bags, and there’s a small possibility that the larger one will need to be checked in the hold – this is called a "gate check" and happens if it’s oversized or if others ahead of you have hogged all the overhead-bin space and you cannot find any space. Note that available overhead-bin space may be some distance from your seat.

The smaller bag can fit under under the seat in front of you, provided there actually is a seat in front of you – so check the airplane seat map and make sure there is one.

Now that you know what dimensions and weights are permitted for a carry-on bag, you can pack your valuables accordingly.

If it’s valuable to you and you can’t fit it in carry-on, don’t bring it.

Checked baggage is for clothing, toiletries, and other expendable items that you could replace at the other end if you needed to. Losing a checked bag is an annoyance and an expense, but not world-ending. They sell shirts in Texas. Really.

Err on the side of traveling light for your first flight adventure.

I have had things stolen from inside bags (the bag disappeared at LAX and reappeared some days later emptied of the important bits). Solution is not to put anything that is especially valuable to others into your bags. Unless you’re a superstar nobody wants your underwear, toiletries and reading materials.

I have had things stolen on an aircraft. Having talked to the flight crew chief whilst waiting for the police to arrive and do their (useless) form-filling, I found that it’s not that unusual, particularly in business and first class. That about ruined my trip, if truth be told. Just have to be a bit more careful and less trusting.

Although I’ve taken a lot of buses, I’ve never had anything stolen on a bus (save some minor pickpocketing attempts and one rather impressive success in France from my companion on the airport terminal shuttle). Nor has anyone ran off with my stuff when the door under the bus opens at a prior stop. Same with trains, though I’m sure I pre-empted it at least once (nervous rough guy walking back and forth through the train scoping out poorly watched bags) Maybe we don’t let our guard down as much on more public transit.

Although I’ve worried about it, I’ve never had a notebook computer disappear when I’ve left it in my room (as I usually do).

I would recommend to watch your stuff in particular before arrival(s). It’s very easy for a thief to escape in the melee that occurs after disembarking. And do NOT think you’re safe on an international flight behind customs barriers. You’re not.

In short, you can’t. It happens but is an increasingly rare occurrence as more automation improved tracking and reduced manual labor involved.

The universal advice is never to pack valuables in checked luggage. Following this advice not only reduces the potential loss to you but also diminishes interest from thieves. It happens since some thieves take their chances that someone packs something of value but given that so many suitcases don’t contain anything valuable, only a few try. Keep in mind that baggage claim is within an airport and entrance is generally restricted which limits who can get close to your luggage.

In many wealthy countries with low crime-rates, you simply take your luggage out without checks but in a lot of other countries, security double-checks that the tag on your luggage matches the number of a coupon that is handed to your when checking in. Be sure to take that coupon too when using self-checkin as it is usually printed onto one strip of label. The larger part goes onto your luggage and a small part detaches as tracking number of every piece of luggage you check-in. We had a case of baggage theft that made the news a few years ago since numerous suitcases kept going missing from Vancouver airport.

Accidental theft is possible but can be greatly diminished by using distinct luggage. I have switched to bright colored bags after several trips to the luggage lost+found and noting that nearly every piece there is black! No brightly colored bag of mine was ever lost again. None of my black bags were ever stolen but several were misplaced by luggage handlers, even not unloaded and hopping onto the next flight.

Theft by airport personnel is not unheard of, particularly in poorer countries. A simple luggage lock, although quite easy to break, makes luggage ever so slightly more difficult to reduce chances of someone peeking in to see if there is something valuable. Even using a twist-tie or belt around the luggage will reduce changes that your bag gets targeted.

Definitively stolen or lost bags are extremely rare (about 0.025%). What does happen in a few instances (though again, this is very rare, but a little less rare than the whole bag being lost or stolen, still less than 0.1%) is theft of valuables inside your bag. The solution for that is easy: don’t put valuables in your checked bag.

It does indeed happen that people pick the wrong bag on the baggage claim delivery belt and only notice once they get to their hotel or home. Again, this is extremely rare, and there’s a pretty simple solution for that: make sure your bag is different from the others. Add a coloured strap around it, for instance, or distinctive stickers.

What is a bit more likely is that your bag may be delayed (Woohoo, a whopping 0.44% chance!). The usual reasons for this are very short transfers where you make the connection but your bag doesn’t, and late check-in. In both cases your bag will be on the next flight, which may be a few hours later or a few days later, depending on the route. The airline will usually arrange to have it delivered to your place in that situation, and they will pay for essentials in the meantime (of course be wary of their definition of "essentials" and the associated procedures).

If you know you are likely to have a very short connection it may be good idea to pack a few essentials in your carry-on.

Source for the figures

I have travelled quite a bit over the years, and I only remember one instance of delayed luggage (short connection) and one of damaged luggage. You are way more likely to get bored to death waiting for your bags to be delivered than anything else. Especially in CDG. Yawn.

Talking about carry-ons, there are usually two different size limits. The smaller one allows you to put the bag under the seat in front of you. This is OK for shorter flights, but not advisable for longer flights in coach as you will most definitely want that space for your feet. Also, you won’t be able to do that if you’re in the first row or any emergency exit row (one of the 3 reasons I avoid row 1 like the plague… Row 2 is soooo much better).

Larger bags go into the overhead lockers, with two caveats:

• On some aircraft the overhead lockers are tiny, so many of those bags will be "gate-checked", i.e. put into the hold either at the boarding gate or at the foot of the stairs into the aircraft. Depending on the route, you will then get your bag back either right when exiting the aircraft, or they will be delivered like checked bags.

• Even in "regular" aircraft, capacity in overhead lockers is limited. If the flight if full, not all large carry-ons may fit in the overhead lockers. If that happens, larger bags will be gate-checked as well, either once the lockers are full, or preventively when they know they won’t all fit.

Depending on the airline and fare, you may be allowed only one bag of either size, only one bag of the smaller size, or one of each. Depending on that, the type of aircraft, and how full the flight is expected to be, there may be different strategies in terms of number and size of bags, but you should make sure that anything essential (passport, medication…) and valuables remain with you on board in any situation.

The chance of checked luggage being stolen or damaged or taken by mistake or just disappearing is vanishingly small. But it does happen. If you cannot relax about it, you won’t enjoy the trip.

Thus, checked luggage should not contain irreplaceable, expensive, fragile, or unique items. The airline’s Terms & Conditions will probably disclaim responsibility for these sorts of items in any event.

Checked luggage should contain only items that can be easily replaced. Remember that no matter where you’re going (except, perhaps, to Antarctica), you will find stores and commerce.

Irreplaceable, expensive, fragile, or unique items should not be contained in checked luggage. Either bring them with you into the cabin, or ship them separately with appropriate packing using a reputable courier with package tracking.

In your cabin baggage (or on your person) should be your electronics, medicines for the entire trip, and travel documents, plus anything else that you’ll know you’ll want to get to during the flight. Many also carry an overnight’s worth of clothes and underwear in case of unexpected on-route delay.

Pre-covid, my wife and I regularly traveled for a month or two at a time with no hold luggage at all, each of us carrying into the cabin one small backpack and one small roller case. As Robert Browning and Mies van der Rohe and others have observed: less is more.

In principle, yes, this can happen. In practice, it is very rare. Speaking personally, in years of travelling, I have only ever once had someone try to walk off with my own luggage … and that was on a suburban bus on my way home. (I never did figure out if they were an opportunistic but incompetent thief, or just someone a bit drunk and confused.)

There are a couple of anti-theft measures that do appear sometimes. In some airports, there are baggage checks – people are stopped on their way out and asked to show the claim tickets for their bags. (You are given these with your boarding pass.). In some circumstances, you may also be stopped for customs inspection (when arriving from international flights), which would be a problem if your bags clearly did not belong to you.

There are other factors that help mean theft is mostly quite low-probability. The first is that most luggage isn’t really that valuable. It’s worth something to the owner, but to most other people it’s fifteen kilos of laundry, and 50:50 chance it’s not even clean laundry. If people are transporting valuables, they usually do so in their hand luggage – you won’t find many laptops or cameras in suitcases. You might get lucky… but you probably wouldn’t.

The second is that most baggage claim areas are not open to the public; everyone standing around is another passenger (or airport staff). Not that everyone who takes a plane is scrupulously honest – but it’s a lot of effort to go to to have a chance of stealing a suitcase!

Thirdly, most of the time, the reason there is a scrum at baggage collection is because all the passengers have arrived before the bags do. Everyone is looking out for their own bag and trying to get to it first. In these circumstances, you’d have to be a pretty bold thief to try and pick up a bag without the owner spotting and confronting you.

People picking up the wrong bag does happen, however, but mostly due to innocent confusion – especially if you all went to the same shop and bought the same range of luggage. The best approach here to make sure no-one gets your bag by accident is to make sure it is visibly yours – a popular approach is to put a brightly coloured address label on it, for example (always a good idea anyway in case it gets accidentally put on a plane to the wrong destination), or something like tying a coloured shoelace/ribbon around the handle.

So while your luggage being taken by someone else intentionally is not a very high risk, you can mitigate the chance of it happening by accident quite easily – just make sure your luggage is distinctive enough that someone else with the same suitcase won’t think "oh, that’s mine".

Lastly, as I mentioned, you can carry high-value items in your hand luggage while putting your clothes, etc in the hold luggage. I think everyone would recommend this if possible – if your bag does get lost, much easier to deal with buying some new shirts than a new laptop.