I am traveling LAS -> ATL -> JFK -> FRA. I fly with the same airline company (Delta) and hence will be only in their terminals (I think so) in each one of the US airports.

My question is whether I have to go through the security check also at JFK and ATL? I have very short layover and afraid to miss the flights.

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    Also, keep in mind if you have one ticket even if you miss the flight they will simply put you on the next one, i.e. by missing the flight you don't lose money (but obviously time).
    – dirkk
    Jun 30, 2017 at 8:14

3 Answers 3


For connections with the same airline you will almost never need to re-clear security - and certainly with Delta at the airports you've listed you will not need to. Delta do operate from 2 terminals at JFK (Terminal 2 and 4), but offer an airside bus between these terminals so there is no need to clear security.

There are two major exceptions to this. The first is when you are arriving from an international destination, in which case you will need to re-clear security after going through immigration at your first port of entry. This isn't relevant for the itinerary you've listed, but might be (for example) on the return trip.

The second exception is if your flight is a codeshare flight with another airline. eg, if your last leg was a Delta flight number but actually on Air France then you would need to re-clear security in JFK to get to the terminal that Air France flies from. However I don't believe Delta have any codeshares between JFK and FRA again this is probably not relevant here.

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    @WGroleau I'm sure what Doc means is that only Delta currently operates SkyTeam flights JFK-FRA, so there is no need to worry about going to Terminal 1 for this connection. Out of JFK, AF flies only to CDG and KLM only to AMS.
    – choster
    Jun 30, 2017 at 21:56
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    Being a codeshare has nothing to do with it. It's whether or not you have to go to a different terminal that's only accessible by leaving the secure area. For example, at Atlanta, all the terminals are accessible from one another without leaving the secure area, so you don't need to re-clear security when connecting (except, as noted, to transfer from an international arrival to a domestic connection); at JFK, the different terminals are only accessible by leaving the secure area so you need to re-clear security any time you change terminals. Jun 30, 2017 at 22:53
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    @WGroleau I'm well aware Delta codeshares with KLM, AF and many others (in fact, I'm flying a DL codeshare with KLM tomorrow, and an AF one in a few weeks), but neither of those airlines flies JFK-FRA.
    – Doc
    Jul 1, 2017 at 6:04
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    @Doc So, if it turns out that the asker's flight is a codeshare but flown on a Delta plane (and it almost certainly is: most transatlatic flights these days are codeshared), they'll have to go through security again, right? Wrong. So, if the asker's flight was actually with a different airline but not a codeshare at all, they wouldn't have to go through security again, right? Wrong. Having to go through security again is not determined by whether or not your flight is a codeshare. Jul 1, 2017 at 12:18
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    @DavidRicherby we obviously have some imprecision around the term "being a codeshare." What Doc obviously means, as stated in his answer, is flights on a Delta ticket operated by another airline. As you have noted, such a situation at JFK would in fact normally require clearing security.
    – phoog
    Jul 1, 2017 at 17:33

Doc has explained Delta at JFK above; I'll take ATL. ATL is my home airport (and I have also changed planes here a time or two before it was my home airport). All terminals here are behind the same set of security checkpoints. For a domestic-to-domestic change, which this is (LAS-ATL-JFK; the fact that you're eventually continuing transatlantic is irrelevant here) there is definitely no clearing security.

ATL is a large airport (and you may have to cross a large portion of it, since Delta operates out of most, or maybe all, terminals) but it's easy to navigate. Each terminal is essentially one long hallway. There is a train that runs underneath the airport (the "plane train") that connects all the terminals; the stop is at the middle of the terminal. Gates are numbered like "A12" which is in terminal A. Really the only trick is that the terminals run in the order T, A, B, C, D, E, F.

  • Good answer, but just one quibble on terminology (and I bring it up only because it could potentially cause confusion.) ATL has only 2 terminals, domestic and international. T, A, B, C, D, E, and F are concourses. The T concourse is attached to the domestic terminal (which is why it's called 'T,' as that was the only terminal until relatively recently) and the F concourse is attached to the international terminal at the opposite end of the field. Once airside, though, you can indeed access any gate from any other gate, which thankfully makes connecting there easy.
    – reirab
    Jul 2, 2019 at 6:10
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    That's a good point. If we're handling ATL nomenclature, I'd also note that the domestic terminal has two entrances, North and South (i. e. not-Delta and Delta), which is relevant if you're originating or terminating there and need to stop at the check-in counter, for example to check bags. (But if you use the wrong one that just means you'll have to walk further.) This would not be relevant for the question-asker who was only making a connection at ATL. Jul 2, 2019 at 13:02

Generally, your domestic flight discharges into the domestic sterile area, and you can hop right on any other domestic flight on any airline. Airlines' domestic terminals are usually interconnected.

Not all airports have their domestic terminals interconnected (typically due to facility constraints, e.g. Detroit). Last time I was at Long Beach, there were two "terminals" in temporary buildings each with their own TSA security line. JetBlue dominates the airport, so even JetBlue thru-passengers had to re-clear.

As choster observes, airports with smaller international trade probably won't have a separate international terminal, their international gates are commingled with domestic gates, and domestic to international transfers aren't so bad. (the trouble with the reverse is the need to clear customs; customs areas are usually set up to dump you into non-sterile areas.)

Some airports with dedicated international terminals, have the desired connection or shuttle bus between domestic and international areas, so you don't have to re-clear. Even if it has one, it may not work for you. Take SFO: it's a hot mess. The new international terminal is stacked practically on top of the domestic terminals - a sterile-area connector is easy. But they hadn't built the connectors by 9/11 and paused after that. They finally opened one side in 2009, which serves only from domestic terminal 3 to international G, not reverse due to Customs exiting into the public area. And domestic 3 doesn't connect to 1 and 2, and international G and A wings don't connect. So it's weak tea that only works for one airline. ORD has similar issues. LAX is now better for some transfers.

Unlike at SFO, the separation is often a simple facility constraint - series of expansions often end with terminals some distance apart. It's not like airport managers are twirling their moustache going "How can we force passengers through security twice, hahahaha!"

And that's what you're up against at JFK. The poor international-terminal connections are part of the greater problem of poor sterile connections generally amongst the many terminals. That is one reason many advise to avoid transferring at JFK.

It's just an unfortunate side effect of multiple expansions at the busiest airports, from which so many international flights operate.

  • What is your home airport? There is usually no domestic vs. international distinction as far as departures go, and a domestic-to-international connection on the same airline does not usually necessitate re-clearing security in my experience.
    – choster
    Jun 30, 2017 at 21:23
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    Given that many other airports have had airside connectors between "domestic" and "international" terminals build in recent years (SFO in 2009 and LAX in 2016 are two that spring to mind) I seriously doubt much of what is written above is correct.
    – Doc
    Jul 1, 2017 at 6:07
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    @Doc that's why I used the word may. I am trying to imply most domestic terminals are interconnected and some international terminals are interconnected to domestic. Is there a way I could have said that better? Jul 1, 2017 at 7:40
  • @Doc I've revised my answer. I wish you had not extrapolated so much based on what "springs to mind". I discuss the SFO connector at length, it's far weaker than the press release claims. ORD seems just as bad. The existence of a connector is not a cure-all, and international arrivals have it worse, due to clearing CBP. Jul 1, 2017 at 18:05
  • The connector between T3 and Intl G at SFO exists because they are the only 2 terminals where a single airline operates out of multiple terminals (United Airlines, which runs 100% of the flights from T3, and over half from Intl G). The connector operates in both directions (I regularly walk from Intl G to T3). Intl arrivals are completely irrelevant as the need to re-clear security is due to government regulations, and occur at ALL airport. For that situation, there is a landside connector. To keep this on topic, if you're not changing airlines at SFO, there's no need to reclear security.
    – Doc
    Jul 3, 2017 at 7:16

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