You hand over a suitcase at a desk, it slides through a rubber curtain, and roughly 40 minutes later it appears on a carousel a thousand miles away. In between, it has been X-rayed by a machine looking for explosives, thrown down a chute, flung sideways off a tray moving at walking-jogging speed, stacked in a heated compartment under your feet, and scanned somewhere between four and a dozen times. Almost all of that happens without a human ever touching it.
Here is the whole journey, the point at which bags actually go missing, and what happens to the suitcases nobody ever comes back for.
Step one: the tag is the bag
The moment your case is weighed, a printer spits out a licence-plate tag: a ten-digit number encoded as a barcode, wrapped around the handle. Nothing else about your bag matters to the system after this. Not the brand, not the colour, not your name. The system moves a number, and your suitcase happens to be attached to it.
That is also why the ripped-off tag is the single most common way a bag becomes an orphan. A case with no readable tag drops out of the automated system entirely and has to be identified by hand, often by opening it.
Step two: the machine that is looking for a bomb, not a thief
Behind the curtain, your bag goes almost straight into an explosive detection system, a CT scanner that builds a three-dimensional image and analyses the density of what is inside. Every checked bag on a commercial flight has been screened this way since the early 2000s, when 100 percent hold-baggage screening became mandatory in the US and then across Europe.
The important thing to understand is what the machine cares about. It is looking for the density signature of explosives, not for your laptop or your watch. If it flags something, the bag is diverted to a second, slower level of screening where an operator looks at the image, and only then, if the image cannot be cleared, is the bag opened by hand. In the US that is when you find the TSA’s notice of inspection inside.
Step three: the part that looks like a theme park ride
Cleared bags join the sortation system, and this is the genuinely impressive part. Your case rides a conveyor through a network of scanners reading that barcode from several angles at once, then transfers onto a sorter, typically a tilt-tray or cross-belt machine that can move in the region of 3,600 bags an hour per lane at speeds around two metres per second. When your bag reaches the chute for your flight, the tray tilts and your case is flicked off sideways and slides down to a make-up area.
There, a handler stacks it into a container or straight onto a cart. That handler is very often the first and only person to touch your bag between check-in and the aircraft.
A note on the hold itself, because this worries people: the cargo compartment of an airliner is pressurised and heated, the same as the cabin. It is not a freezing void. That is precisely why animals can travel there.
Where bags actually go missing
The industry measures this obsessively, and the numbers are much better than the internet’s reputation for them.
According to SITA’s 2026 Baggage IT Insights report, the mishandling rate fell 23 percent in 2025 to 4.9 bags per 1,000 passengers, below pre-pandemic levels for the first time, even with five billion people flying. That is 24 million bags out of roughly five billion journeys. Mishandling has dropped by around three quarters since 2007.
It still costs the industry $6.3 billion a year, about $260 per bag. SITA’s own framing is brutal: a single mishandled bag wipes out the profit on more than 30 seats, and five of them erase the profit on an entire flight.
And the location of the problem has barely moved in twenty years. Transfers are 39 percent of all mishandling. Your bag is far more likely to be lost changing planes than at either end of the journey. If you have a 45-minute connection and your inbound flight lands late, the aircraft can make it while your suitcase does not, because your bag has to be pulled from one container, re-sorted and re-loaded in a window measured in minutes.
Which leads to the single most useful thing in this article: a mishandled bag is usually a delayed bag, not a lost one. The overwhelming majority turn up within a day or two. Genuinely lost bags, the ones that never come back, are a small fraction of a small number.
Why the barcode is slowly being replaced
A barcode has to be seen to be read. If your bag lands tag-down on the tray, if a frequent-flyer sticker covers it, if the label is scuffed or wet, the scanner gets nothing and the bag falls out of automation.
RFID fixes this, because the tag does not need line of sight. Airlines that have rolled it out at scale report tracking accuracy above 99 percent, and the industry standard behind all of this, IATA Resolution 753, requires airlines to track every bag at four points: handover from the passenger, loading onto the aircraft, transfer, and delivery back. Compliance passed the 50 percent mark industry-wide in 2025, with full adoption targeted for 2027. Half of airlines say they will give passengers real-time bag tracking within two years.
It is worth remembering how badly this can go. Denver International Airport built the most ambitious automated baggage system ever attempted; it shredded suitcases in testing, delayed the airport’s opening by 16 months at roughly a million dollars a day, and was finally abandoned altogether in 2005 in favour of conveyor belts and people.
What happens to the bags nobody claims
If a bag cannot be matched to a passenger, it goes to a central tracing centre, where staff open it and work backwards from the contents: a prescription label, a business card, a name tape on a child’s coat. Most bags are reunited this way.
The ones that are not have a genuinely strange ending. After a set period, commonly 90 days, the airline settles the passenger’s claim and the bag is written off as salvage. In the United States, essentially all of it ends up in one place: Unclaimed Baggage in Scottsboro, Alabama, a shop the size of a city block that buys unclaimed suitcases from the airlines sight unseen, sorts and cleans the contents, and sells them. Around 7,000 items hit the shelves every day. It has become a tourist attraction in its own right, which tells you something about human curiosity.
Six things that actually reduce your risk
- Book longer connections. Transfers cause 39 percent of mishandling. A 90-minute connection is a different risk profile from a 45-minute one.
- Rip off the old tags. Every stale barcode on the handle is something a scanner or a handler can read by mistake.
- Put your name and number inside the bag as well as outside. Tracing centres open bags. Make their job take five seconds.
- Photograph the bag and its contents at check-in. It turns a claim from an argument into a form.
- Drop a tracker in. Airlines increasingly accept a passenger’s own tracker location as evidence of where a bag is, which shortens the conversation enormously.
- Keep medication, documents and one change of clothes in your cabin bag. Because the realistic bad outcome is not “lost”, it is “two days late”.
If you want more of what goes on out of sight on your flight, our piece on what flying actually does to your body covers the passenger side, and what happens when a bird hits a plane covers the part everyone worries about for the wrong reasons.
Frequently asked questions
How often do airlines lose luggage?
Mishandling fell to 4.9 bags per 1,000 passengers in 2025, a 23 percent improvement on the previous year and below pre-pandemic levels. The great majority of those are delayed rather than permanently lost.
Where do most bags go missing?
In transfers. Changing planes accounts for 39 percent of all mishandled bags, because the suitcase has to be unloaded, re-sorted and re-loaded in a very short window.
Is the luggage hold pressurised and heated?
Yes. The cargo compartment is pressurised and temperature-controlled like the cabin, which is why animals can be carried there.
Are checked bags searched?
Every checked bag is screened by a CT-based explosive detection system. Only bags the machine and then a human operator cannot clear are physically opened.
What happens to unclaimed luggage?
After the airline settles the claim, commonly at 90 days, the bag is sold as salvage. In the US almost all of it goes to Unclaimed Baggage in Scottsboro, Alabama, which sells the contents at a discount.
Sources: SITA Baggage IT Insights 2026; IATA Resolution 753; Unclaimed Baggage, Scottsboro, Alabama.
