Alert areas may contain high volume of pilot training or an unusual type of aerial activity. MOAs (located over land) and warning areas (located over domestic or international waters or both) and training routes contain high volumes of military activity.
Areas that require caution due to high volumes of pilot training or unusual aerial activities include alert zones, which can be found over land or water.  Military activity is also concentrated in areas designated as MOAs (over land) and warning areas (over domestic or international waters). Training routes are also known for their high levels of military activity.