In the old days of analog cell phones, a single cell phone would talk to all the towers in range and hog bandwidth on every one. On the ground not many towers were in range, once you got to 20,000 feet, there were a lot. If cell phones were on on all the planes over LA, it would be like a DDOS attack.
Possibly still an issue with digital phones, but they can do a lot of smart things, modulate power, drop calls to not overload the network LOL.
The cell phone ban is an FCC ban, not FAA like devices during takeoff and landing - http://www.fcc.gov/guides/wireless-devices-airplanes
In the old days of analog cell phones, a single cell phone would talk to all the towers in range and hog bandwidth on every one. On the ground not many towers were in range, once you got to 20,000 feet, there were a lot. If cell phones were on on all the planes over LA, it would be like a DDOS attack.
Possibly still an issue with digital phones, but they can do a lot of smart things, modulate power, drop calls to not overload the network LOL.