The FCC has elected to maintain its ban on the use of cell phones during airline flights. Three years ago the FCC agreed to re-examine the rule, but ultimately found that there was "insufficient technical information" about how cell phones in the air interact with cell towers below. The FCC also received many letters during its public comment phase urging it to keep the ban, though the agency says it ruled purely on technical constraints.
Conspiracy theories about crowd control notwithstanding, the main concern seems to be that a phone in flight could potentially tie up resources at dozens of cell towers as it continuously searches for the best tower. The FAA also maintains a separate ban on the use of cell phones in flight on the basis that they may interfere with aircraft avionics.