1. 航空的；飞机的；由飞机进行的；空中的
You talk about aerial attacks and aerial photographs to indicate that people or things on the ground are attacked or photographed by people in aeroplanes.

2. 空气中的；地表以上的
You can use aerial to describe things that exist or happen above the ground or in the air.

3. 天线
An aerial is a device or a piece of wire that receives television or radio signals and is usually attached to a radio, television, car, or building.