The third aircraft had been shot down by anti-aircraft guns, which is why Kelly found the downed plane full of holes. Both pilots had enough time to press the eject button and jump out of the falling plane before it hit the ground. However, they didn't manage to make it too far.
The pilot had miscalculated the ejection and landed only a few feet away from the crash site. A sharp wedge of metal had broken off from the downed plane and impaled his chest. His skeleton was lying on top of a semi-truck, with a portion of the plane's wing shoved into his ribcage.
As Kelly walked up to the downed plane, she discovered the corpse of the co-pilot lying a few feet in front of the crash site. His body had been ripped in half by something sharp and heavy. The acid rain had dissolved his uniform and flesh, but he was still recognizable from the half-burnt commercial airliner cap lying beside him.