I live in New Jersey. One thing I will always remember on that horrible day was how stunningly and so strikingly blue the sky was. It made the smoke and flames all the more horrid and ugly.
I remember the blue skies and the silence, except for the occasional military jet patrolling the area. At the time, I lived within the landing pattern of EWR, JFK, LGA, HPN, and SWF, and at any given moment, there were usually several commercial jets circling the airports waiting to land. But then the skies shut down, and there was silence — blue skies and dead, eery, silence.
I also recall seeing what I later found out was AA Flight 11 flying low down the Hudson River Valley, low even for a jet landing at nearby SWF or HPN, the two closest airports to my house. A few minutes later, FR Breaking News reported the first crash into the WTC North Tower.