Makes sense.
“Was the Drone/UAV Hovering in the JFK Landing Approach Kill Zone (LAKZ) a Failed Terrorist Attack?”
http://www.freerepublic.com/focus/f-bloggers/3014942/posts
There was NO radar return for the multi-copter that missed the Alitalia airliner by 200 feet five miles out on the runway 31R landing approach at about 1,500 to 1700 feet altitude.