This will fail for commercial reasons.................

Airlines want to do this to make money! The charges will not be your normal cell charges, but special (high) rates for connecting you via the "cell" fitted to the aircraft.
All analagous schemes have failed COMMERCIALLY, not technically... eg.
- in flight phones - exist, but are hardly used and known to be a money loser for the companies running them and for airlines
- in flight internet access - provided by Boeing, now closing the unit after 6 years and removing the service from the carriers who have it. See http://www.boeing.com/news/releases/2006/q3/060817a_nr.html

Combine the suspect econmomic case with the evident annoyance this will generate in many passengers and wise airlines will not even go there. The ones that do will discontinue it in a few years - because it will lose money, not because it won't work or is unsafe in any way.
At that point their problem will be that people will have worked out that using a cellphone in an aircraft is just fine (except for sensible reasons of caution during take off and landing). What will then do then???