الشركة تؤجل الرحلة البديلة.

Because شركة is a grammatically feminine noun. A very common sign of feminine gender in Arabic is the ending ـة (tāʾ marbūṭa), and شركة has it.

So even though a company is not biologically female, Arabic still treats الشركة as feminine for grammar. That affects agreement, including the verb form.

In the present tense, Arabic uses different prefixes for different persons and genders. Here, تؤجل is the 3rd person feminine singular form: she/it postpones.

Since الشركة is grammatically feminine singular, the verb matches it:

• الشركة تؤجل = The company postpones
• If the subject were a masculine noun, you would usually get يؤجل

So the تـ here is there because the subject is feminine singular.

Since the sentence begins with الشركة (a noun), many grammar descriptions treat it as a nominal sentence:

• الشركة = the topic / subject
• تؤجل الرحلة البديلة = a verbal clause acting as the predicate

If you changed the order to تؤجل الشركة الرحلة البديلة, that would be a more clearly verbal sentence.

In English, both usually translate the same way, but in Arabic the starting point of the sentence matters grammatically and stylistically.

Yes, that is also correct.

Both of these are grammatical:

• الشركة تؤجل الرحلة البديلة
• تؤجل الشركة الرحلة البديلة

The difference is mainly in sentence structure and emphasis:

• الشركة تؤجل... starts with the company as the topic
• تؤجل الشركة... starts with the action

In many contexts, the meaning is basically the same.

Because in Arabic, adjectives normally come after the noun they describe.

So:

• الرحلة البديلة = the alternative flight

This is the opposite of normal English word order, where the adjective usually comes first:

• English: the alternative flight
• Arabic: the flight alternative

Because Arabic adjectives must match the noun they describe in definiteness.

Here, الرحلة is definite: the flight.
So the adjective must also be definite: البديلة = the alternative.

That gives:

• الرحلة البديلة = the alternative flight

Compare:

• رحلة بديلة = an alternative flight
• الرحلة البديلة = the alternative flight

This matching of definiteness is very important in Arabic.

A few clues show that it is an adjective:

First, it follows the noun it describes, which is the normal adjective position in Arabic.

Second, it matches الرحلة in the ways adjectives are supposed to match nouns:

• both are feminine singular
• both are definite with ال
• both would have the same case ending in fully vocalized Arabic

So الرحلة البديلة is a noun + adjective phrase, not a construct phrase (iḍāfa).

A useful contrast:

• رحلة بديلة = an alternative flight
• رحلةُ الشركةِ = the company’s flight

In an iḍāfa, the structure looks different.

In fully vocalized MSA, the sentence would be:

الشَّرِكَةُ تُؤَجِّلُ الرِّحْلَةَ البَدِيلَةَ.

The endings are:

• الشركةُ = nominative, because it is the subject/topic
• الرحلةَ = accusative, because it is the direct object of the verb
• البديلةَ = accusative too, because the adjective matches الرحلة

In normal Arabic writing, these short vowels are usually omitted, so learners have to infer them from grammar.

Yes. الرحلة is the direct object of تؤجل.

The verb أجّل / يؤجّل means to postpone / delay, and it takes a direct object: you postpone something. In this sentence, the thing being postponed is الرحلة البديلة.

So:

• الشركة = the one doing the action
• تؤجل = postpones
• الرحلة البديلة = the thing being postponed

It is pronounced roughly tuʔajjilu.

A helpful breakdown is:

• tu
• then a glottal stop ʔ (the hamza)
• then ajjil

So it is not pronounced like tuwajjil. The hamza is a real consonant sound.

This verb comes from أجّل in Form II, meaning to postpone. In fully vocalized form, the present tense here is تُؤَجِّلُ.

It is not pronounced the same way in all three words.

• الشركة is pronounced ash-sharika, because ش is a sun letter, so the l of ال assimilates.
• الرحلة is pronounced ar-riḥla, because ر is also a sun letter.
• البديلة is pronounced al-badīla, because ب is a moon letter, so the l is pronounced normally.

So the spelling always has ال, but the pronunciation changes depending on the next letter.

It can mean either, depending on context.

The Arabic present/imperfect often covers both:

• The company postpones the alternative flight
• The company is postponing the alternative flight

If you want to make the action clearly future, Arabic often adds something like:

• ستؤجل = will postpone
• سوف تؤجل = will postpone

Without extra context, تؤجل is simply present/imperfect and can be interpreted in more than one way.