Witnesses of United Flight 93 crash on 9/11

Witnesses of the United Flight 93 crash on 9/11 report seeing a white plane swooping in low, as low as 40 meters above, circle twice above the crash site just after the crash. The plane was seen just before the crash as well. There were six witnesses of this plane. All except for one say they are sure it was at the time of the crash they saw this white plane.

Video is from Internet Archive:

http://www.archive.org/details/GNN_Flight93_Pt2