Considering that on Sky City/Aquanos, the copter dropzone is very, very far from the defenses, on aqua it's near the mid-up crystal, and on Sky City it's almost everywhere, on the pathway from mid to south where there is a chest, on the pathway with a fan on southwest, on the enemy spawn midwest before the 4 fans for North... and also just a little above the middle crystal , behind the walls.
Those copters will at 99% chance drop their ogre safely,and by no means can be killed by defenses/dropped by heroes (with a barbarian...lol? only safe way to get the normal ogres)