Breakdown of Я всегда приезжаю за полчаса до вылета.
я
I
всегда
always
приезжать
to arrive (by vehicle)
до
before, until
Questions & Answers about Я всегда приезжаю за полчаса до вылета.
How does the за ... до ... structure work in this sentence?
This structure means a certain amount of time before an event. Here, за is followed by the amount of time in the Accusative case (полчаса), and до is followed by the event in the Genitive case (вылета). Think of it literally as saying you arrive "by half an hour until the departure."
Why does полчаса not change its ending after за?
The preposition за requires the Accusative case here, but полчаса (half an hour) is an inanimate compound noun that has the exact same form in both the Nominative and Accusative cases. It's built from пол- (half) and часа (Genitive of час).
Why use приезжаю instead of прихожу for "arrive"?
Both mean to arrive, but Russian distinguishes how you travel. Приезжаю is the verb for arriving by transport (like a car, bus, or train), which is usually how one gets to an airport. Прихожу would mean you arrived entirely on foot.
Why is the imperfective verb приезжаю used instead of a perfective one?