A fifty caliber rifle which can hit a 3' circle at 2,000 yards would be able to hit the 12' diameter jet intake at a mile with no problem.
A likely sniper's lair would be a soundproofed van or truck parked along the flight path.
A NON-MOVING 3' circle at 2000 yards.
Sounds like the same "rightwing" group that spread the anthrax around. Now we have a leed.....