watashi wa ashita no hikouki no yoyaku o shimasu.

topic particle

Breakdown of watashi wa ashita no hikouki no yoyaku o shimasu.

• 私わたし: I
• の: possessive case particle
• 明日あした: tomorrow

Questions & Answers about watashi wa ashita no hikouki no yoyaku o shimasu.

Why do we use は instead of が in 私は?

The particle は marks the topic of the sentence (“as for me”). In this case you’re stating something about yourself: “As for me, I will make….” Using が would emphasize the subject in a different way (“It is I who will…”), but は is most natural to introduce your topic.

Why is there a の after 明日?

That の is the genitive/possessive particle linking two nouns. Here 明日 (tomorrow) modifies 飛行機 (flight), so 明日の飛行機 means “tomorrow’s flight.” In Japanese you often use AのB to mean “B of A.”

Why is there another の between 飛行機 and 予約?

Again you have AのB: 飛行機の予約 means “reservation of a flight” or “flight reservation.” You’re turning 予約 into a noun phrase that describes what is being reserved (the flight).

Could I say 飛行機を予約します instead of 飛行機の予約をします?

Yes.

• 飛行機を予約します literally “I reserve the flight” (verb-centered).
• 飛行機の予約をします literally “I make a reservation of the flight” (noun + する).
  They’re equivalent in meaning; the first is slightly more direct, the second emphasizes the action 予約をする (“to do a reservation”).