CT Scanners at the Airport, Liquids Gone at the Connection: the 2-Litre Trap
8 min read
I was standing at the gate with a 1.5-litre water bottle sticking out of my backpack, completely relaxed about it. CT scanner at the airport, liquids up to 2 litres allowed, I had read that two weeks earlier. At the first security check it was true. Two hours later, at my connection, the bottle was gone.
Departure went exactly the way I had read about
Backpack on the belt. Nothing unpacked, no plastic bag, no laptop in its own tray. The officer barely looked up.
Which is the problem, honestly. A smooth run through security feels like confirmation that the 100 ml era is finally over.
It isn't. Around 700 approved CT scanners are in use or being installed across 21 EU countries, according to ZDFheute. That's a lot of machines. Just not everywhere at once.
My sister Nina, who flies far more than I do, actually warned me beforehand. "Check the second airport too," she said. I didn't. I was already through.
Then came the second checkpoint
On a connection you often have to clear security again. I knew that part. What I hadn't thought through: the second screening follows the rules of the airport you are standing in, not the one you left.
The bottle went into the bin. The officer glanced at it, shrugged, said they were still on the old rule here. No argument, no drama. Just that stupid feeling of having walked into something avoidable.
Other travellers hit the same wall. Travel And Tour World reports a passenger losing a family-size bottle of suncream at a connecting hub. Her line afterwards was "I thought the rules had changed everywhere." That's the whole mistake in seven words.
The nastier version shows up in a FlyerTalk thread: the CT scanner at London Heathrow Terminal 5 went down briefly, everyone was redirected to the legacy lane next to it, and a bottle of Italian sparkling water was confiscated on the spot. Same airport, same checkpoint, different rule. Within minutes.
And that's the bit that genuinely annoys me. Not the bottle. The fact that checking in advance doesn't reliably protect you either.
Why CT scanners at the airport don't cover the same liquids everywhere
The rollout happens lane by lane. Not per country, not per airport, not even per terminal.
At Frankfurt Airport, Germany's biggest hub, roughly 40 of about 190 security lanes have been converted, with 40 more on order, according to europeannewsroom.com. So the large majority of lanes at a major transfer airport still run the old rule.
Milan is stranger still. EU Perspectives reports that Malpensa Terminal 1 allows 2-litre containers while Terminal 2 of the same airport keeps the 100 ml limit. A few hundred metres apart, two different answers to the same question. Reading that, I honestly stopped wanting to know how many lanes at my own home airport are converted.
Munich's hub isn't much further along: German federal police told aero.de they'd need 60 CT scanners there and currently have 20 in use. Even one of Germany's biggest airports is only partway through, and the gap between terminals is real.
The Commission reversed itself once already
Per Euronews, the European Commission restricted approval of these scanners in summer 2024 and only re-issued it in 2025. That new approval initially covered one manufacturer's hardware. Airports that had bought early from a competitor are still waiting on separate recertification.
Honestly, at that point I stopped trying to keep the details straight. One manufacturer, one approval, one reversal, that's a lot even for someone who'd already done the reading. It isn't a single decision that flips the rules overnight. It's years of construction, airport by airport, lane by lane.
And nobody's job is to warn you
Commission spokesperson Anna-Kaisa Itkonen told EU Perspectives that the responsibility to inform passengers still sits with individual airports. Not with Brussels.
Which answers my "why did nobody tell me" question completely. There is no office whose job that is.
What I do differently now
The sentence that stuck with me comes from UK consumer group Which?: the rules apply where you get screened, not where you take off. Which? also states outright that a 2-litre bottle permitted on the outbound leg may well not be permitted coming back.
For German airports and terminals, our own CT scanner tracker has the current state. The full list of EU airports allowing 2 litres sits in our 2-litre rule overview. I now check both of those before any itinerary with a connection, for both legs.
And I still pack for the stricter one. A converted lane can go offline, and then you're standing at the old one.
A clear bag costs you nothing
That's exactly what I could have used at my connection. The 1-litre clear bag is probably the cheapest piece of travel kit in existence, and the only one that clears every checkpoint in Europe, and if you want the details on which bag actually passes and what size it's allowed to be, we cover that in our guide to liquid travel bags. At a CT lane you don't need it. It doesn't hurt you there either.
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Bottles, so you're not rebuying at the connection
Nina told me afterwards that this is exactly why she's carried a fixed set of small bottles for years, whatever airport she's flying through. Suncream, shampoo, contact lens solution. Anything that lives at home in family size becomes a liability at your second airport. A set of 100 ml bottles solves it once and then never again. Not glamorous, but it works. How many bottles realistically fit in the bag is something we covered separately in How Many 100ml Bottles Can You Bring.
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Two bags, because outbound and return are two checkpoints
This is almost exactly what caught me out again on the way home. The return leg is what almost everyone forgets. A spare bag in your checked case means you're not hunting for one at the resort if the local checkpoint is stricter than the one back home.
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A screenshot of the airport's security page
Sounds excessive, takes twenty seconds. Your connecting airport's security page usually states what applies there right now. And if someone at the checkpoint pushes back, at least you have something. It's no guarantee. It might do nothing for you at all. I'd still rather have had it.
Honestly? It's irritating, not unmanageable
I never missed the bottle. What stuck was the feeling of getting caught out by something that ought to be simpler than buying the ticket.
Maybe this is sorted in two years, once every airport's CT scanner covers liquids properly. Maybe not, given how often the timeline has already slipped. Until then the bag weighs nothing, and you can still buy water on the other side of security.
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Frequently Asked Questions
Does the 2-litre rule apply everywhere in the EU?
No. The allowance depends on the individual security lane being CT-equipped, not on the country and not even on the airport. At Milan-Malpensa, Terminal 1 allows 2-litre containers while Terminal 2 of the same airport still enforces the 100 ml limit. That exact gap between two checkpoints was my own trap.
Are these new rules for the plane, or just for security?
Just for the security checkpoint. Nothing changes on the plane itself, and your airline has nothing to do with the allowance. What you can carry is decided entirely by the equipment at the specific lane you walk through, not by the airline and not by the aircraft.
What happens to my liquids when I connect?
On many connections you get screened again, and the rule of the airport you're standing in applies. If it has no CT lanes yet, anything over 100 ml gets pulled, even though your departure airport allowed it. There's no replacement and no compensation.
How do I find out whether my airport has CT scanners?
The airport's own security page is the most reliable source, since operators are the ones responsible for informing passengers. For German airports we maintain a tracker with the status per terminal. That's what I check now before every connecting flight. Don't rely on general headlines announcing that the 100 ml rule has been abolished.
Do I still need the clear bag if my departure airport has CT scanners?
Not at a CT lane. I'd pack it anyway. If that lane goes offline you get redirected to the legacy checkpoint, where the bag requirement is back, which is exactly what happened at Heathrow Terminal 5.
Are duty-free liquids safe on a connection?
Only up to a point. The sealed duty-free bag with its receipt isn't recognised everywhere, especially when you connect outside the EU. If you want certainty, buy larger liquids at the last airport of your trip.
