Did United 93 passenger Jeremy Glick call with a cellular phone on 9/11?

Question

In the "September 11 - The New Pearl Harbor" documentary (1:46:45), a claim is made that Jeremy Glick used a cellular phone to make a roughly 20-minute phone call to his wife and mother-in-law. While it is known that he did make a phone call, the documentary emphasizes that it is highly unlikely a 20-minute long cellular phone call could be made back in 2001, when the plane was flying an at altitude of 39,000 - 10,000 feet going around 400 mph.

To support their claim that Glick made a suspicious phone call, they cite two FBI documents.

I looked around, and was able to find the first document (here and here (pg 13)), which was consistent with the one presented in the documentary:

Lyzbeth could not hear any unusual sounds in the background of the call and the connection was extremely clear, "as if he was calling from the next room."

However, I could not find the second document, which is far more important as it supposedly notes that

Glick saw hijackers on the plane, used a cell phone & called Makely

and

Cell phone communication was lost at 9:55 AM

(And is the document they cited that specifically states a cellular phone was used)

I have looked around the FBI Vault, but have been unable to find that specific document. I also found a edited, supposed transcript of the phone call involving Glick, where his mother-in-law makes conflicting remarks regarding whether or not he used a cell phone: "He's in the airplane with a cell phone", "He's on the airline plane phone. He's not on his cell phone" (x2).

Is the cited FBI document in the documentary real or fabricated, and did Jeremy Glick use a cellular phone to call his wife & mother-in-law while onboard Flight 93?

Answer 1

Thanks to Ben Voigt's suggestion, I note that 35 of the 37 known calls from the flight were placed using Airfone, including the 20-minute call by Jeremy Glick The linked summary indicates that he used the Airfone in row 27 on the starboard side of the plane (seats DEF). Airfone communicated in a different frequency range (849 to 851 MHz) from cellular telephone service (which uses a complex set of frequency bands that have a gap between 848.8 MHz and 851.2 MHz).

The two calls placed by regular cell phone were both placed at 9:58, which is when the flight first reached 5,000 feet altitude.

(During this time, the plane was above the area between Pittsburgh and Shanksville, above I-76, so probably better supplied with cell towers than other rural areas, so it's not unlikely that those calls could have been handed off from one tower to another. Glick placed his call at 9:37, while the plane was turning around over northeastern Ohio and climbing from 35,000 feet to 40,000 feet.)

Is the cited FBI document in the documentary real or fabricated, and did Jeremy Glick use a cellular phone to call his wife & mother-in-law while onboard Flight 93?

The document appears to be real (thanks to Oddthinking for the link). Jeremy Glick did not use a cellphone to place the call in question. He used an Airfone in row 27.

With thanks to fellow user Nelson, I quote the helpful comment explaining that the existence of an FBI document describing a statement about a cell phone call does not mean that the FBI believes there was a cell phone call:

People need to distinguish the actual witness statement "He used a cellphone", and actual facts of what happened "He used an Airfone". The statement, being a record of what was actually said, will NOT be corrected to Airfone just because it is what actually happened. The witness record is correct in the sense that it is what the witness said, but incorrect in terms of what actually happened.