He had/went for/took a walk, to get some air.

他出去散步，呼吸点新鲜空气。

Now where can I get some air miles again?

现在我还能在哪里得到航空里程呢？

When a dolphin is injured, other dolphins help it swim up to the surface and get some air.

如果一只海豚受伤了，那么其他海豚也会帮助它一直游到岸边以呼吸新鲜空气。