I think this is the pertinent passage from that article:
The gliders have the ability to fly at low altitudes and controlled, low speeds, which may be useful in search-and-rescue operations and some types of surveillance.
I have seen gliders here in Tennessee many times and they can go right over the trees very low, and this time of year they can see all the way to the ground. So if some clothing was dumped in the woods they could see it.
My only problem is that any clothing discarded before the leaf dump would be covered by leaves right now. A body/skeleton too, for that matter. It wouldn't take much work to hide a body from the air.
Karen Swift was found by two people in the cemetery on foot, by the way, and not from the air. It was Gail Palmgren who was found from the air but only with infrared sensors that found her rather large Jeep. I doubt that her body was visible from the air because at first they couldn't find it since she was thrown out of the Jeep.