בשער העלייה היה כתוב שהטיסה מאוחרת, אבל אחר כך היא יצאה.

בשער העלייה means at the boarding gate.

It is made of:

• ב־ = in / at
• שער = gate
• העלייה = the boarding

The phrase שער העלייה is a construct chain: literally the gate of the boarding, i.e. the boarding gate.

In a construct chain, the first noun usually does not take ה־. The definiteness comes from the second noun. So:

• שער עלייה = a boarding gate
• שער העלייה = the boarding gate

That is why you do not say שער ההעלייה.

Not in this sentence.

The noun עלייה can mean different things depending on context, all related to the root עלה (to go up). In airport language, עלייה means boarding. So שער העלייה is the boarding gate.

In other contexts, עלייה can mean immigration to Israel or aliyah, but that is not the meaning here.

היה כתוב is a very common Hebrew expression meaning:

• it was written
• it said
• it was posted / written there

So in this sentence, היה כתוב שהטיסה מאוחרת means something like it said that the flight was delayed.

Literally, כתוב means written, and היה makes it past: was written.

This phrase is often used impersonally, without naming exactly what was written on. English might say the sign said... or it said...; Hebrew often just says היה כתוב...

Because here the phrase is being used impersonally.

Hebrew often uses היה כתוב as a kind of fixed expression meaning it said / it was written, without an explicit noun like the notice or the sign.

If you did mention a feminine noun, then you would normally match it:

• ההודעה הייתה כתובה על המסך = the notice was written on the screen

But in this sentence, there is no explicit feminine subject. So היה כתוב is the normal default form.

The ש־ means that.

So:

• שהטיסה מאוחרת = that the flight is delayed

This ש־ is extremely common in Hebrew. It introduces a clause, just like that in English.

Examples:

• אני יודע שהוא כאן = I know that he is here
• אמרו שהחנות סגורה = They said that the store is closed

Because Hebrew does not always do the same tense backshifting that English often does.

In English, after a past verb like it said, we often say:

• it said that the flight was delayed

In Hebrew, it is very common to keep the tense that reflects the actual message itself:

• שהטיסה מאוחרת = that the flight is delayed

This sounds natural because the sign’s message was essentially the flight is delayed.

So even though היה כתוב is past, the content of the message can stay in the present.

Because טיסה (flight) is a feminine singular noun.

In Hebrew, adjectives, pronouns, and past-tense verbs usually agree with the noun they refer to.

So:

• הטיסה מאוחרת = the flight is delayed
  (מאוחרת is feminine singular)
• היא = she / it referring to the flight
• היא יצאה = it departed
  (יצאה is feminine singular past)

English uses it for things, but Hebrew still uses grammatical gender, even for inanimate things.

Here מאוחרת means late or delayed.

With flights, trains, buses, and similar things, Hebrew often uses מאוחר / מאוחרת in the sense of delayed.

So:

• הטיסה מאוחרת = the flight is delayed / late

It is the feminine singular form because טיסה is feminine.

יצאה is the feminine singular past form of יצא, which literally means went out / went forth / left.

In transportation contexts, it often means:

• left
• departed

So here אבל אחר כך היא יצאה means but afterward it departed.

Even though the basic meaning of יצא is go out, it is very commonly used for buses, trains, flights, and similar things leaving.

אחר כך means after that, afterward, or later.

It is a very common time expression in Hebrew.

So:

• אבל אחר כך היא יצאה = but afterward / later it departed

You will hear אחר כך all the time in speech and writing.

Hebrew word order is fairly flexible, and it is very common to put a place or time phrase at the beginning to set the scene.

So בשער העלייה היה כתוב... is like saying:

• At the boarding gate, it said...

This is natural Hebrew. You could also rearrange parts of the sentence in some contexts, but the given order is very normal and helps establish where the information appeared right away.