Assuring luggage isn't lost with short layover

With a connection time of slightly under an hour, you're right that it's a possibility your bags won't make the connection.

It's quite likely that your bags will be labelled (or marked in the electronic tracking system) as "hot", meaning "get this bag off the plane and onto the connecting flight ASAP".

Re-checking your own luggage at Atlanta probably wouldn't help, if anything it would make things slower, as you'd have to wait for your luggage, queue up to drop it off then possibly re-clear security.

Changing your first flight might help, but it's important to remember that nothing will guarantee that your bag makes the connection. If it doesn't, the airline will usually deliver it (at their expense) to wherever you're staying, so as long as you can go a day or two without your bag, you'll be fine.

I do not think this is a concern: transferring luggage is easy going, especially as your luggage will not have to be screened again since you are a domestic arrival. Moreover DL and KLM have a highly integrated system, and the airport in Atlanta handles more than 100 million passengers a year: barring some unexpected event if you can make it to the flight - terminal transfer and all - then with high probability your luggage will make it too.

Remember also that luggage is often being loaded when passengers have already boarded, often up to the very last moments before departure.

The worse possible option is to ask to recheck your luggage in ATL: you’d have to first wait for your luggage, wait in line to drop it, go through security again while your luggage is re-screened, and the transfer to the international terminal. I doubt this can be done in 55 minutes.

You might worry if your luggage requires special handling because of weight or size.

Of course not checking luggage (if practical) is the best guarantee.

Nota: as far as I can tell, the latest statistics by the US government are for August 2018. The stats for Delta are on page 36: they have just less than 0.2% mishandled bags (i.e.less than 2 mishandled bags in 1000). (see also here). From the title, this only reflects reports filed by passengers.

Short of arranging a longer connection (which may involve the payment of change fees) or shipping your luggage ahead (which, itself, may be result in it becoming delayed or lost), there's not really anything you can do as a passenger to ensure your bags are transferred at your connection. They're supposed to be, and airlines generally do a pretty good job of it these days, but it doesn't always happen.

Which means the best thing you can do is to prepare for the possibility that your bag may not arrive with you. Carry a change of clothes. Pack essentials in your carry-on; never check medication, toiletries, electronics, or valuables. If you're traveling with someone else, cross-pack, with some of your items in their suitcase, for redundancy if only one bag doesn't arrive (though in the case of a tight connection, it's likely either all or none of your bags arrive). If your bags don't make it, sigh, file a report, and move on: you've prepared so it won't be a significant problem.

As Kate Gregory notes in comments, it's not unheard of to have the reverse problem: your bag makes the connection but you do not, especially if your flight is delayed. Preparing in this way means you'll have necessary supplies for your extended layover while you wait for another flight.

Beyond that, consider the worst-case scenario. For many trips, the worst that will happen if your luggage is delayed is you get tired of wearing your backup clothes until your delayed luggage arrives and you go to the nearest H&M or Primark to buy something new (for which reimbursement from the airline or travel insurance may be possible). Irritating, but not a huge problem. For other trips, missing luggage could be a showstopper: weddings without wedding dresses, backpacking trips without backpacks, film productions without cameras. Trips where you immediately head into the middle of nowhere or board a ship pose difficulties in arranging to be reunited with your luggage. If that's the case, plan ahead, allow extra time, and prepare a contingency plan.

Frankly, there's not much you CAN do, and I would advise against re-checking your own luggage as this would make your connection tighter.

Personally, I have had some really tight connections at busy hubs (50 min at DUB in Dublin, 1 hr at JFK in New York, and 1.25 hr at LHR in London) and I have never had any issues. Missed connections for luggage are the exceptions, most of the time it works seamlessly. Enjoy your trip and don't worry about it! :)

Luggage delays happen, and sometimes (often?) they'll be out of your control. What you can do, however, is to mitigate the consequences.

In addition to the packing recommendations suggested in the other answers, perhaps the way to go is just to get adequate travel insurance so that if your luggage is delayed, you'll be able to re-purchase whatever items you urgently need without bothering about the cost.

It is a valid concern.

Landing in Atlanta, checked bags will be unloaded and sorted. Only those with final destination Atlanta will be brought to a baggage carousel. Bags checked for a connecting flight will be taken from plane to plane.

Unloading, sorting and loading with some transporting in between will of course take a little while, but in some cases this is completed before passengers have disembarked.

There is never any guarantee that bags will make a connection, but a longer layover does increase the chances. A 53-minute connection will work under normal circumstances, but your chances would be far better will an additional hour or so, especially if your first flight is slightly delayed. Also consider that a short connection also increases the risk of you missing your connecting flight.

• A 53-min (same-terminal, same-carrier/codeshare) connection at ATL is normal and generally you would expect the bag would make your flight like 90+% of the time, else it should come on next flight (and they have a van service to deliver to your hotel/location).

• plan your luggage so that documents, valuables, urgent items, chargers, essential toiletries, change of clothing etc. are in carry-on.
• you can get compensated for buying replacement essentias if it's more than X hours late, see regulations
• basically don't worry. It shouldn't get lost. You can't (economically) "assure" luggage isn't lost, you can only mitigate the impact.

• These days, the likelihood that your bag makes the connection depends less on how tight the connection time is, and more on how much $$ fare you paid and what status you have on that carrier, with legacy US carriers these days (AA, Delta, UA). Your only defense (other than paying $$ for premium economy/business) is to pick one carrier/partner/alliance and accrue status on it. Or else fire the legacy carriers and fly Norwegian/Level/WestJet/AirTransat(->about to be acquired)/etc.

• as illustration, one time I got a cheap flight to Toronto (with Northwest, since acquired by Delta) which required an overnight layover in Chicago, where I had to sleep on a bench in ORD in a closed area for 5 hours. But at least I figured my luggage would make that connection with all of 6hrs. No! What happened was it was transferred and loaded early, then unloaded later to make room for luggage of passengers with higher status)