How Your Checked Baggage Travels From Counter to Plane
You check your bag and it disappears behind a rubber curtain. The next time you see it – ideally – is on the carousel a few hours later. In between, it moves through a system most passengers never see.
The sorting belt and first scanner
After check-in, your bag enters the baggage handling area – the BHS (Baggage Handling System). It’s a network of conveyors: a few hundred meters in smaller airports, up to 30 km of belt in large ones, like Amsterdam’s Schiphol, which processes 50 million bags a year.
The first thing it hits is a barcode or QR code scanner on the tag. The scan is automatic – no human involved. The system reads the 10-digit number on the tag. That format is called the IATA 10-digit bag tag – a standard set by IATA, the International Air Transport Association. The same number is printed on the receipt stub you get at the check-in counter. That number tells the system which flight your bag belongs to and where it needs to go.
If the tag is crumpled, wet, covered in tape, or partly hidden by the bag’s handle – the scanner won’t read it. The bag gets pulled for manual sorting. During peak hours, manual sorting can delay a bag long enough that it misses the flight. Before you check in, make sure the tag is stuck to a flat surface and fully visible.
Security screening: CTX and the HBS zone
Before your bag reaches the ramp, it goes through HBS (Hold Baggage Screening). The standard in most countries is a five-level process.
- Level 1 – an automated CTX scanner (computed tomography). It produces a 3D image of the contents, and an algorithm flags potential explosives based on density and shape. That’s why you don’t take your laptop out of a checked bag – the CT scanner sees through the layers.
- Level 2 – a second automated pass if the first result was inconclusive.
- Level 3 – a human operator reviews the image on screen.
- Level 4 – physical inspection: the bag is opened. In the US, TSA (Transportation Security Administration) leaves a printed “Notice of Baggage Inspection” inside. European airports typically don’t leave any notice.
- Level 5 – the passenger is contacted, or law enforcement is involved.
Most bags clear Level 1 only. A single pass through a modern CTX scanner takes about 30 seconds.
How the ULD system works
After screening, the bag moves to the flight-sorting area, where it’s loaded into a ULD container.
ULD (Unit Load Device) – standardized containers and pallets used to consolidate baggage before it goes into the aircraft. The point is to avoid loading bags one by one: you fill the container in advance, then roll the whole thing into the cargo hold in minutes.
The codes LD3, LD6, LD11 are IATA designations for different container types. Each is sized for specific aircraft models:
| ULD type | Dimensions (L×W×H) | Aircraft | Capacity |
|---|---|---|---|
| LD3 | 156×153×163 cm | Boeing 767, 777, A330, A340, A350, A380 | ~4.5 m³, up to 1,590 kg |
| LD6 | 318×153×163 cm | Boeing 767, 777, A330, A350 | ~8.9 m³, up to 3,175 kg |
| LD11 | 318×244×163 cm | Boeing 747, A380 | ~14.2 m³, up to 6,033 kg |
| Pallet P6P | 318×224 cm | Boeing 747, 777, A380 | depends on load height |
Narrowbody aircraft – Boeing 737, Airbus A320, A321 – can’t take ULD containers. Bags go in loose (“bulk loading”), loaded by hand. It’s slower, which is why delays and lost bags happen more often on short-haul budget flights.
On narrowbody aircraft, the cargo hold isn’t sealed off from fuel systems as thoroughly as on widebodies (twin-aisle jets like the Boeing 747, 777, 787, A330, A350, A380). During manual ramp loading, bags spend time next to running ground equipment. That’s where the fuel smell on your A320 bag comes from.
Connecting flights and MCT
Nearly half of all lost bags go missing during a connection. At a hub airport, the system has to do a lot in a short window: read the tag from the inbound flight, route the bag through the BHS to the right terminal, run it through screening again if needed, and load it into the ULD of the outbound flight – all within the MCT (Minimum Connection Time).
MCT is the official minimum connection time at a specific airport. A few examples:
MCT is the minimum for the baggage system, not for you personally. You can walk to the gate in 20 minutes. Your bag takes a different route – through the BHS, sometimes through another terminal.
Book a connection right at MCT and your bag has a high chance of not making it. A reasonable buffer is MCT plus 30-40 minutes.
If your first flight is on one airline and your second is on another, and they’re not alliance partners, your bag may not be checked through. This comes down to an interline agreement – a deal between carriers that allows through-check of baggage. Without one, you’ll need to collect your bag at the first airport, clear customs, and re-check it. At the check-in counter, ask whether you’re getting boarding passes for both flights – if yes, the bag is checked through.
The ramp: the last 200 meters
A loaded ULD or a cart of bulk bags gets towed to the ramp by a baggage tractor. Between leaving the BHS and going into the aircraft, everything happens outdoors – rain, snow, 40°C heat. This is where bags fall off carts during sharp turns. Not often, but it’s exactly why wheels snap off and scratches appear.
Loading into a widebody uses a Hi-Loader – a raised platform that brings the ULD up to the cargo door level. For narrowbodies, a standard conveyor belt angles bags down into the hold at about 30 degrees. Handlers receive them at the bottom and stack them by hand.
Why bags get lost: the actual numbers
According to SITA Baggage IT Insights 2025 (SITA, the Swiss company that provides IT infrastructure for most of the world’s airlines), 6.3 bags were delayed or lost per 1,000 passengers in 2024 – down 67% from 2007, when the rate was 18.9 per 1,000. The number keeps dropping each year, driven by RFID adoption and AirTag integration into tracking systems.
The global average hides a wide gap between regions:
| Region | Lost per 1,000 passengers (2024) | Main causes |
|---|---|---|
| Asia-Pacific | 3.1 | Fewer connections, stricter process discipline |
| North America | 5.5 | Large hubs, frequent domestic connections |
| Europe | 12.3 | Complex EU connections, ground staff strikes, aging infrastructure |
A bag is nearly four times more likely to go missing in Europe than in Asia. If you’re connecting through Frankfurt, Heathrow, or Madrid, build in more time – and don’t check anything you can’t survive without for a couple of days.
How those losses break down by cause, per the same SITA data:
| Cause | Share of cases |
|---|---|
| Transfer failure | ~41% |
| Loading failure | ~17% |
| Routing error, check-in error, mis-sort | ~16% |
| Operational causes (weather, aircraft capacity, customs) | ~10% |
| Loading errors (wrong container, equipment failure) | ~8% |
| Arrival and offload failures | ~4% |
| Tag errors (torn off, unreadable) | ~4% |
On a direct flight, the risk of losing a bag is 3-4 times lower than on a connection. When you’re choosing between two tickets, a direct flight usually costs a bit more – but it often saves you a day of stress in an unfamiliar city with nothing to wear.
Why Asia loses fewer bags
3.1 losses per 1,000 passengers across Asia comes down to several factors working together:
- Newer infrastructure. Most Asian hubs were built after 2000. Kansai International (KIX) in Osaka opened in 1994, and according to the airport, not a single bag has been permanently lost since. KIX handles around 10 million bags a year. In 2024, it received the Skytrax World’s Best Airport for Baggage Delivery award.
- Process discipline. At Kansai International, the count and type of bags on every flight are independently verified by at least two staff members. If the numbers don’t match, work continues until every bag is accounted for. Fragile items are delivered by hand rather than run through the conveyor. Bags that get rained on are dried before loading.
- Automation. Changi Terminal 2 in Singapore has used a fully automated early baggage storage system since 2024 – 2,400 bags on individual trays managed by robotic cranes. Incheon (Seoul) records roughly one lost bag per 100,000 passengers – an order of magnitude better than most Western hubs.
- Operational stability. Japan, South Korea, Singapore, and Taiwan essentially don’t have ground staff strikes. Germany, France, Italy, Spain, and the UK deal with them regularly, and every strike produces thousands of delayed and lost bags.
If your itinerary connects through Seoul, Singapore, or Tokyo, the statistics are on your side – more so than a connection through London or Frankfurt.
RFID, barcodes, and AirTag
A paper barcode tag reads correctly about 85-90% of the time on a single scanner pass. An RFID tag: 99.9%. RFID (Radio-Frequency Identification) is a tiny chip inside the tag that responds to a radio signal and transmits the bag number. The percentage gap sounds small, but across 50 million bags a year it translates to millions of correctly routed bags.
IATA made RFID tags mandatory under Resolution 753 in 2018. The standard requires airlines to track bags at 4 key points: check-in, loading, offloading, and delivery. Delta Air Lines (as early as 2016) and Lufthansa were among the first to roll out RFID across their entire networks. As of end of 2025, 80% of IATA member airlines have a full deployment plan, but only 29% have the infrastructure actually in place.
In November 2024, SITA integrated Apple Find My (the Share Item Location feature in iOS 18.2) into its WorldTracer system. If you put an AirTag in your bag and share the location link through your airline’s app, the coordinates go directly into the system used by Lost & Found agents – not just to your phone. According to SITA’s data from the first year of integration, passengers with AirTag saw permanently lost bags drop by 90%, and average return time for delayed bags fell by 26%.
By December 2025, 29 airlines had joined the integration, including Delta, United, American, British Airways, Lufthansa, KLM, Air France, Singapore Airlines, Qantas, and Turkish Airlines. If your carrier is on that list, an AirTag or Tile actually functions as a recovery tool – not just a map on your screen.
But an AirTag doesn’t obligate the airline to act. In 2025 there were several high-profile cases: Air France ignored a shared location and the bag eventually turned up at a second-hand shop near Paris. United, in one incident, refused to call the airport where a bag with an AirTag was sitting – the passenger ended up flying there herself. An AirTag gives you facts to bring to the service desk and grounds for a formal claim. It carries no automatic legal weight.
What to do when your bag doesn’t show up
If the belt has stopped and the last passenger has left but your bag isn’t there, go straight to the Lost & Found desk – don’t leave the arrivals area first. Once you’ve cleared customs, proving that bag was checked on that specific flight becomes technically harder.
The airline opens a report in WorldTracer – an international database connected to more than 500 airlines and 2,800 airports. Using the 10-digit tag number, the system locates where the bag got stuck.
Three main outcomes:
- Delayed – the bag has been found at another airport or on a different flight and will be delivered within 24-72 hours. The airline is required to bring it to your address at their expense.
- Misrouted – the bag went to the wrong destination. This happens with similar IATA city codes: Portland, Oregon (PDX) and Portland, Maine (PWM) are a real source of mix-ups on US domestic routes.
- Lost – if the bag hasn’t been found within 21 days, it’s officially declared lost.
Once a bag is officially lost, you’re entitled to compensation under the Montreal Convention – a 1999 international treaty ratified by 140 countries that sets airline liability for lost or damaged baggage on international flights.
The compensation limit is reviewed every 5 years for inflation. From December 28, 2024, it stands at 1,519 SDR per passenger. SDR (Special Drawing Rights) is the International Monetary Fund’s unit of account, a basket of five currencies (US dollar, euro, yuan, yen, pound sterling). In practical terms, 1,519 SDR works out to roughly $2,020 or €1,860 at May 2026 exchange rates. The rate floats, so the exact figure changes. This is the maximum you’ll receive without a prior declaration of value, regardless of what the bag actually contained.
While your bag is in transit, you’re entitled to reimbursement for essential purchases – a toothbrush, underwear, basic clothing, toiletries. Keep every receipt.
The legal term is “reasonable expenses” – things you need right now, without going upmarket. A toothbrush and a T-shirt: yes. A new Rolex to replace the one in your bag: no.
In Europe, this right flows from the Montreal Convention. EU261/2004 doesn’t apply to baggage situations – that regulation covers flight delays, cancellations, and denied boarding only. In the US, the Montreal Convention is supplemented by DOT (Department of Transportation) rules. The DOT requires US carriers to cover necessary purchases and sets its own compensation cap for domestic flights: from January 22, 2025, that’s $4,700 per passenger – higher than the international Montreal Convention limit.
There’s no fixed daily amount for “reasonable” expenses anywhere in the rules. In practice, airlines tend to accept $50-150 per day, depending on the country and circumstances. Spend more than that and you’ll need to justify each purchase individually.
One more change from 2024 in the US: baggage fees are now refunded automatically. If your bag on a US domestic flight isn’t delivered within 12 hours of arrival (15 hours for international flights under 12 hours, 30 hours for long-haul international) and you’ve filed a Mishandled Baggage Report, the fee comes back automatically. This is on top of any compensation for the bag’s contents under DOT rules or the Montreal Convention – not instead of it.
What actually reduces your risk
Most advice online covers the obvious – bright tags, distinctive luggage. What actually affects routing:
- Remove old tags before every flight. Especially barcodes – the scanner can pick up an old tag instead of the new one if both are visible. This accounts for 3-5% of routing errors.
- Check in your bag at least 45 minutes before departure on domestic flights, 60 minutes on international. Every airline has its own cutoff, but a bag checked in later than that has little chance of making it through the full BHS in time.
- Put an Apple AirTag or Tile inside your bag. If your airline is connected to the SITA WorldTracer + Apple Find My integration, share the location through the airline’s app – the Lost & Found agent will see the coordinates, not just you. That’s what drives the 90% reduction in permanently lost bags in the 2025 data.
- Don’t wrap your bag tightly in plastic film. Locks crack during manual loading on narrowbody aircraft, and handlers wrap a burst bag in film right on the ramp. The tag usually gets lost in the process.
- Photograph your bag before check-in – with the lid open. It won’t speed up the search, but it makes filing a claim much easier: you’ll have proof of what was inside.
- Book direct when you have the option. Half of all losses happen at connections.
About luggage locks
If your bag is selected for a physical inspection, it will be opened – locked or not. That’s a legal right of security services, and you can’t contest it. The only thing your lock affects is whether it gets cut off or opened cleanly.
There are two main categories:
- TSA locks – marked with the Travel Sentry logo (a red diamond with TSA printed on it) or Safe Skies (a white torch). US security services have a universal master key that opens any of these without damage. After the inspection, the lock is closed again.
- Non-TSA locks – combination locks without the TSA logo, padlocks, and locks from European or Asian manufacturers without Travel Sentry certification. If your bag gets inspected, these get cut off with bolt cutters. You won’t be compensated for it – you chose a lock outside the recognized standard.
In the US, you can technically file a claim with TSA if they damage your bag or a TSA-certified lock during inspection. That means going through the standard SF-95 form, a process that takes several months and results in many claims being denied. In practice, it’s easier to keep a spare TSA lock in your bag or accept that locks are consumables.
Outside the US – in Europe, Asia – the TSA logo has no legal significance. Local security services can open a lock however they choose. But most do use standard Travel Sentry master keys, since the tool is common across the industry.
A TSA lock isn’t foolproof, but your chances of getting your bag back with an intact lock are noticeably better with one than without.
Only if your airline offers it in their app. Delta, Lufthansa, Air France, Emirates, and a handful of other carriers on RFID infrastructure show bag status updates: “accepted”, “loaded onto aircraft”, “offloaded”. If your airline isn’t on that list, an AirTag or Tile gives you more accurate information than any official tracking.
Three main possibilities: the bag was bulk-loaded last and is offloaded last (normal for oversized bags, which are loaded first and come off last), it’s going through additional customs screening, or it didn’t make it onto the flight. If the belt is empty and your bag isn’t there – go to the Lost & Found desk. Don’t wait.
The bag is pulled from the flight. This is a security requirement in place since the 1988 Lockerbie bombing over Scotland: every checked bag must travel with its passenger. Locating and offloading the bag of a no-show passenger is one of the main causes of departure delays. A single no-show can hold a flight for 20-40 minutes.
Two reasons. First, security cut the lock during a physical inspection (HBS Level 4) – a standard non-TSA lock gets cut off and doesn’t get replaced. Second, manual loading on narrowbody aircraft: bags slide down a conveyor belt under their own weight, and a weak zipper splits. The fix: a hard-shell bag and a lock with the Travel Sentry or Safe Skies logo – those are opened with a master key, not bolt cutters.
At a major hub, 20 to 45 minutes under normal load. During peak hours – the morning departure wave at Heathrow, Frankfurt, or Dubai – it can stretch to 60-90 minutes. That’s why airlines close baggage check-in 45-60 minutes before departure: it’s not bureaucracy, it’s a real constraint of the system.