My girlfriend said that the closest air port to manhatten is about a 1/2 hour away so I think poeple should get alarmed because of a low flying plain if the closest air port is 1/2 hour away
From downtown where the WTC was:
La Guardia - 6 miles northeast
JFK - 8 miles east
Newark - 7 miles west
At a 200 mph approach speed it is 2.4 minutes to JFK and 1.8 minutes to La Guardia.