Here you are simply instruction how to make metal peel of area on the aircraft surface. First at all, you need to spray some good surface on the top, in this case this is Base White. Next to do is to make very smooth surface and use 4000 to 6000 grit sanding paper. After that spray coat of silver paint. Spray it on surface where you need to do peel of paint and it is important to check out available images for precise details. When silver paint is completely dry, spray a thin coat of hair style spray. It need to dry from 10 minutes up to 30 minutes maximum. After that spray camouflage colors over, single or several, no problem at all.
When top coat of paint is dry, take short and strong brush (most of those for classic oil painting are like that) and with a little water, 'brush' over surface with a stronger pressure. Very soon you will see top color is removing and bottom silver is start to appear. Change brush size, movement and pressure in order to get specific shape of damaged paint.
Model by Tweety