I think a bigger problem is that cellphones go out of range. Once they are off-shore, and 20 or 30 miles from a celltower, they do not work.
Some have commented on how phones worked during 9/11. That’s not relevant here, because the 9/11 plane paths were entirely over land, where cell towers are plentiful.
My Verizon cell phone works reliably from cruising altitude, but my previous Sprint phone did not. (NB: non-passenger airplane!)
“I think a bigger problem is that cellphones go out of range. Once they are off-shore, and 20 or 30 miles from a celltower, they do not work.”
That is all out the window. As it does not work that way. While on the plane cell phones communicate with the planes communication system. The plane then talks directly with a satellite which then communicates with the ground phone system. So in essence the plane itself is a cell tower. It is this system in the plane that sent all the final pings to the satellites. And it also explains the actual communication with cell phones that were still turned on when loved ones tried to call in.
It is possible that the cell phones were collected by terrorists. It is also possible that all normal passengers were already dead according to some theories.