They are tuning up a plane on the flight line.

他们正在机场的飞机跑道上调试一架飞机。

From the flight line it's on to the Forums Area.

从飞机保养区来到论坛区。

We went to the base that you worked at and went on the flight line.

我们到了您工作的基地，走到起飞线上。

Please lead me to my flight line and I will show you which one is my baggage.

请带我去取行李，我会指给你看哪个是我的。

Draw a line from your position to form a right Angle to the ball's flight line.

从你的位置往球的飞行路线上画一个直角。