I don't like driving long distances - I prefer to go __ air.

• A. By
• B. In
• C. On
• D. With

Answer: (A)

The main idea here is how we express the way we travel. When talking about the method of travelling, English uses the preposition by with a noun that names the transport, like by car, by train, or by air. In this sentence, the contrast is between driving and air travel, so the natural phrase is go by air.

The other options don’t fit because they don’t form a standard way of saying how you travel: in air isn’t used to describe traveling method, on air is about broadcasting, and with air isn’t a common way to indicate transport. So go by air correctly conveys traveling via air transport.