Relevant info on this topic is accessible through posts #586 and #671 linked below: 4um Title: How 9-11 Was Done
Post #586 -- videos, links, and details Post #671 -- WETA/PBS addendum info
Poster Comment:
Tangential discussion starting point [#103] at 4um Title: Pilots Analyze the Government Provided Radar Data of the Planes of 9-11, if needed for referencing here.