Let’s say I’m flying from Baltimore to LA and changing planes in Chicago.
Does my luggage, in theory, travel on the same flights I do all the way to LA? Or do they use any old routing plan that will work?
I’ve had some strange luggage scenarios happen lately that make me question my assumptions.
I’m pretty sure that your luggage has to travel on the same plane as you’re on. I think it’s a federal regulation. I can’t seem to find a cite for this, though I’m sure someone will come along with one shortly.
Whenever I’ve taken a “voluntary bump” (giving up my seat on a overbooked flight in exchange for some compensation from the airline), my checked baggage flew on the original flight.
A couple of years ago - after 2001, certainly - my wife and I took voluntary bumps at the start of a trip to visit my parents that involved us catching a flight the following morning. The airline apologized, but said that our luggage was on the plane, wouldn’t be unloaded, and would be travelling on the original flight.
We managed a night without our primary toiletries, but ultimately that was no big deal.
We called my parents in the destination city, and they were kind enough to go pick up our checked bags when our original flight landed rather than let them sit unattended in the terminal all night. (They live close to the airport.) We described the bags in detail to my father, and he walked in, found them on the carousel, and walked out unchallenged with them.
Huh. Since 2001 I have been on more than one flight which was delayed while they hunted around to find the luggage of somebody who didn’t make the flight.
I was a bit surprised, myself, given the bluster that I’d often heard about “bag matching” from the airlines.
Unfortunately, it sometimes seems that the airlines choose to invoke these “security measures” in somewhat self-serving ways. (Cite a “federal law” to get a passenger to shut up, but freely violate it when it’s more convenient for them…)
Perhaps I’m wrong, but that is how it often looks to the traveller… 
Not very well, in my opinion.
I don’t know the FAA regs, but it seems to me that “someone checked bags on this flight but never tried to board” would raise more red flags than “someone checked bags and tried to board flight but we bumped them to a later flight”.
That’s an excellent point. It may well be the difference…
To answer the OP, the luggage tag has the airport code for the destination and a bar code which is linked to your itinerary in the computer. The bar code is scanned after you check it and at each intermediate stop to direct your luggage to the appropriate flight. At the last stop it is sent to the baggage carousel in the terminal.
So, barring unusual circumstances your luggage will fly on the same plane with you.
On international flights bag matching is enforced. I have been on flights where we were delayed while the bags of no show passengers were removed from the plane. (How or why in the hell would somebody check into the airport, check bags and then not get on the plane?) I believe this is a federal regulation.
If you were boarded and get bumped sometimes they take your bags off, and sometimes they don’t. I took a bump last year on US Air and they pulled my bags while I watched (the baggage guy held up the bag and waited for my thumbs up) and they sent them over to the next flight. YMMV
If you bags don’t show up, they will fly them on other flights. I had a trip back from Sweden several years ago where there had been a blizzard the night before I left. My flight to Copenhagen was late, and I just made my connection to Seattle. My bag didn’t make it. This really was not a shock considering what the weather was like. Anyway the next day my bag came home via Paris on Air France.
I had a bag not get to Denver on United once. While filing the report, I asked the baggage guy about how big this problem really is. His comment was that they handle about 100,000 bags a day at Denver, on the average they have to deal with 4 or 5 lost bags. What is that a 99.995% percent sucess rate? Pretty good sucess rate if you ask me.
I’ve often wondered about this. Some years back a friend and I flew cross country together on a non-stop flight. We arrived at the airport together, checked our luggage sequentially. When we got to the west coast, my bags were on the carousel and hers weren’t. 
How can bags get lost on a non-stop flight?
Obviously, they didn’t get lost on the flight, they got lost (or misdirected) on the way to the plane. Sometimes that happens.
I thought it was semi-standard practice for just about every airline to give you little packs of toiletries if they lose your bags/strand you somewhere overnight/otherwise screw you over. I’ve never in any of my travels had them offered, but if you request at the baggage office, they’ll generally give you a little pack with a toothbrush, toothpaste, deoderant, etc.
The Albuquerque airport is, completely inexplicably, the only airport I can recall checking that your end of the little sticker thing matches the tag on your checked luggage. It’s only sometimes, but it strikes me as funny that this dinky little nowheresville airport checks that, while none of the major ones do.
FWIW - Always, always, always carry primary toiletries and a change of underwear and socks in your carryon. No matter what. Trust me on this.
Not that I can recall, even in the good old days when there was service. I once made a flight from Chicago to Denver at the last minute - my bag didn’t. to United’s credit, they knew exactly where it was, and it got delivered to me later (much later) that night. In fact every time my bag did not go with me, they knew where it was.
I’ve been delayed on domestic flights as they removed bags.
Before there were bar codes, they printed the airline code of each intermediate flight on the luggage tag.
In any case, if your bags did not follow you, they’d get lost a lot more often. There are not that many ways of going from place A to B, after all.
Ah, those were the good old days. This is no longer so common. Once upon a time in th 80’s, TWA would put me up in a hotel when I was stranded overnight due to weather delays (i.e., not the fault of the airline). The airlines can hardly afford to do that kind of thing nowadays.
They still do give out those little packets ifyour luggage looks like it might be overnight before you get it.
Might be a good idea to gather a few more data points, including some from unbiased sources.
Because the bag contains a bomb and the passenger doesn’t want to be on the plane when it goes off. That’s the only good reason I can think of, aside from sheer forgetfulness or bad luck. In that case, it would be a Good Thing for your bags to stay in the same city you are.
This is what happened in the Pan Am Lokerbie bomb incident . Since then the “matching luggage to passengers policy” has been vigorously pursued in the UK. I have sat on a plane while luggage from a no-show passenger has been off-loaded.
There can be an innocent explanation. The BBC broadcasts a regular documentary series about Heathrow Airport, and time after time they show this. People don’t keep an eye on the departure screens , they get involved in last-minute shopping in the duty free, or decide to have a meal. Then there is a mad scramble to reach the gate , sometimes too late.