Bij de veiligheidscontrole moet u uw jas uitdoen en uw instapkaart laten zien.

Because Dutch often puts a time/place/context phrase at the beginning of the sentence.

Here, Bij de veiligheidscontrole means something like at the security check or during the security screening. It sets the scene first.

Dutch does this very naturally:

• Bij de veiligheidscontrole moet u...
• Op het station wacht ik...
• Morgen gaan we...

When a phrase like this comes first, it affects the word order in the rest of the sentence.

This is because Dutch main clauses usually follow the verb-second rule.

That means the finite verb must come in the second position of the clause.

In this sentence:

• Bij de veiligheidscontrole = first element
• moet = second element
• u = comes after the verb

So:

• Bij de veiligheidscontrole moet u uw jas uitdoen...

If you started with u, then you would get:

• U moet bij de veiligheidscontrole uw jas uitdoen...

Both are grammatical, but the emphasis is slightly different because the first element is different.

Moet is the singular/formal form of moeten, which means must, have to, or need to.

In this kind of instruction, moet expresses obligation:

• u moet uw jas uitdoen = you must / have to take off your coat

In airport or official contexts, Dutch often uses moeten for rules or required actions.

• u = you
• uw = your

So in the sentence:

• moet u = must you / you must
• uw jas = your coat
• uw instapkaart = your boarding pass

Also, u is the formal version of you in Dutch. That is very common in announcements, official instructions, customer service, and polite speech.

Because each noun needs its own possessive word.

Dutch does not normally let one uw cover both nouns in a sentence like this. So you say:

• uw jas
• uw instapkaart

That is the normal and natural way to phrase it.

Dutch forms compound nouns by writing them as one word.

So:

• veiligheid = safety / security
• controle = check / inspection
• veiligheidscontrole = security check

This is very common in Dutch. English often uses separate words where Dutch uses a compound:

• treinkaartje = train ticket
• paspoortcontrole = passport control
• luchthavenpersoneel = airport staff

A useful rule: in Dutch, if English would use a noun + noun combination, Dutch often makes it a single word.

Because both nouns are de-words.

In Dutch, every noun has either:

• de
• het

You usually have to learn this with the noun.

Here:

• de controle
• therefore de veiligheidscontrole
• de kaart
• therefore de instapkaart

In compounds, the final part usually determines the article:

• veiligheidscontrole ends in controle, so it takes de
• instapkaart ends in kaart, so it takes de

Uitdoen is a separable verb.

It is made of:

• uit = out/off
• doen = do

In this context, uitdoen means to take off, when talking about clothes.

Examples:

• Ik doe mijn jas uit. = I take off my coat.
• U moet uw jas uitdoen. = You must take off your coat.

Why is it written together here? Because after a modal verb like moeten, Dutch uses the infinitive at the end:

• moet ... uitdoen

But in a normal main clause without a modal, it separates:

• U doet uw jas uit.

Because Dutch puts the other verbs at the end when there is a modal verb like moeten.

The finite verb is moet, and the other verbs stay in infinitive form at the end:

• moet ... uitdoen
• moet ... laten zien

So the structure is roughly:

• context
• finite verb
• subject
• objects
• remaining verbs at the end

This is a very common Dutch pattern:

• U moet wachten.
• U moet uw ticket tonen.
• U moet uw jas uitdoen en uw instapkaart laten zien.

Literally, laten zien means to let see.

But in normal Dutch, it very often simply means to show.

So:

• uw instapkaart laten zien = to show your boarding pass

This is an extremely common everyday expression. Dutch also has verbs like tonen or laten bekijken in some contexts, but laten zien is very natural and common.

Examples:

• Kunt u uw paspoort laten zien?
• Laat je ticket even zien.

Jas is a general word for an outer garment such as a coat or jacket.

In airport security, uw jas uitdoen usually means taking off the outer layer you are wearing, such as:

• a coat
• a jacket
• sometimes another similar outer garment

So English might translate it as either coat or jacket, depending on context.

It is another Dutch compound noun:

• instappen = to board
• kaart = card / ticket

So instapkaart is literally something like boarding card. In natural English, this is usually boarding pass.

Dutch often builds practical travel vocabulary this way:

• instapkaart = boarding pass
• bagageband = baggage belt
• paspoortcontrole = passport control