When driving around in Israel, about 5 years ago, I noticed a tethered kite, which may have been inflated, holding position about 1500'. It was holding its heading.
When close enough, we could see its tether, and that it was some sort of surveillance platform. It was overlooking an 'occupied territory'.
I remember thinking that compared to any aircraft or chopper, it must be very inexpensive.
Also, because it was there all the time, not intrusive at all.
I wonder what it would have cost the IDF/ AF to gather that same intel by any other means?