First-Responder Eyewitnesses to the Planes that Hit the WTC on 9/11

Note: This is not a comprehensive list.

Most of the quotes listed below are taken from the 9/11 Oral Histories, archived at the New York Times and taken from the World Trade Center Task Force Interviews. They can be found here: 

http://graphics8.nytimes.com/packages/html/nyregion/20050812_WTC_GRAPHIC/met_WTC_histories_full_01.html

This post contains:

• First-Responder Eyewitnesses of the Second Plane on 9/11
• First-Responder Eyewitnesses of the First Plane on 9/11
• First-Responder Eyewitnesses of Airplane Parts / Debris on 9/11
• FDNY Officers' Testimonies to the Condition of WTC7 on 9/11  (unrelated, but interesting nonetheless)