I remember a beautiful, clear, Tuesday morning a few years ago......
OK, how long did it take for the government to shut down the piers in NYC after 9/11?
It took hours to give the order to shut down air traffic, and that was a simple order from the president.
Your timeline is a bit off
8:45 1WTC hit
9:03 2WTC hit
9:17 All NYC area airports closed
9:21 All NYC area bridges and tunnels closed to vehicular traffic
9:40 The FAA halts all flight operations at U.S. airports