New York musician Mark Schaffer, 31, lives on the 16th floor of the building opposite the scene of the plane crash. He told the BBC News website what he witnessed.
Mr Schaffer heard a 'horrifying combination' of sounds
I was on the balcony smoking, facing away from the scene, and I heard the roar of it getting louder and louder.
As a New Yorker, your instinct is to look up. I turned towards it a split second before it hit the building.
There was a small fireball and the front half of the plane disappeared inside the building. The rear half fell 20 stories to the ground.
It was such a horrifying combination of sounds. It sounded much louder than it should be, like thousands of windows shattering. Then people down below started screaming.
The fire is out now and they are starting to clean up the scene. I can see the remains of the plane, with large pieces of debris on the lower tiers of the building.
It's raining now. It's a very grim scene on the Upper East Side of Manhattan today.
There are still sirens and lights on every corner and a great deal of paramedics, firefighters and police officers.
People who either heard or saw this have the potential to be quite traumatised by this. Anyone in the neighbourhood will be pretty shaken.