some quotes and links I found:
from
http://answers.google.com/answers/main?cmd=threadview&id=173057...
“The Federal Bureau of Investigation (FBI) knows from witness accounts
of cell phone conversations with passengers on the hijacked airliners
that the terrorists eluded security measures and used cardboard-box
cutters and razors to take control of the four aircrafts…
United Airlines Flight 93 was airborne by 8:44 a.m., according to
radar logs. At 9:37 a.m., the plane turned south and headed back the
way it came…
Passengers on cell phones learned of the crashes at the World Trade
Center and formulated a plan to respond to the hijackers.”
Source: ‘The Network of Terrorism – The Hijackings’
US Info – International Information Programs
http://usinfo.state.gov/products/pubs/terrornet/print/sbhijack.htm The following are some references of cell phone conversations being
made by passengers on the hijacked airplanes on 9/11.
‘FBI lets Flight 93 families hear tape’
The Washington Times
http://www.washtimes.com/national/20020326-89153745.htm A report from The Associated Press
http://www.achsah.com/fl93.html Post-Gazette.com
http://www.post-gazette.com/headlines/20010920scenenat2p2.asp SCMP.com
http://special.scmp.com/aua/ZZZKOVCVJRC.html WWNF Sept11
http://www.wwnfsept11.com/Heroes_Flight93b.htm CNN
http://www.cnn.com/2002/US/09/03/ar911.phone.calls/ MSNBC
http://www.msnbc.com/news/627214.asp?cp1=1 American Memorials
http://www.americanmemorials.com/memorial/tribute.asp?idMemorial=1320&idContributor=7709 ...
Subject: Re: Do Cell Phones work from jets above 30 000 feet?
From: karlon-ga on 25 Mar 2003 15:21 PST
...
From this morning's New York Times: "According to industry experts, it
is possible to use cell phones with varying success during the ascent
and descent of commercial airline flights, although the difficulty of
maintaining a signal appears to increase as planes gain altitude. Some
older phones, which have stronger transmitters and operate on analog
networks, can be used at a maximum altitude of 10 miles, while phones
on newer digital systems can work at altitudes of 5 to 6 miles. A
typical airline cruising altitude would be 35,000 feet, or about 6.6
miles."