Things that are aerial are happening in the air: birds, planes, and missiles are all aerial things.
When talking about things that are literally up in the air, you can use the word aerial. If a country sends planes to bomb another country, that's an aerial attack. In football, the passing game is called the aerial game. Anything light and airy can also be called aerial, and an aerial is a device that picks up radio or TV signals: it plucks them out of the air. So when you see the word aerial, just think "air."