The Federal Aviation Administration and Boeing, the nation's largest builder
of airliners, both support the F.C.C.'s ban, arguing that cellphones can
interfere with navigation systems.

In fact, European newspapers widely reported that use of a cellphone
contributed to the crash of a Crossair commuter plane in 2000. LX Flight
498, carrying 10 passengers and crew members, was bound for Dresden when it
crashed outside Zurich minutes after it took off, killing all on board.
Officially, the reason for the crash remains unknown. But news reports at
the time said a passenger apparently took a cellphone call at the same time
that the pilot engaged the autopilot controls. The plane subsequently went
into a dive.

Despite such questions, airlines have begun their own tests of whether
cellphone use can be made feasible. A test last July by American Airlines,
the nation's biggest, allowed the use of conventional cellphones to place
and receive calls by way of a picocell - a miniature cell tower the size of
a pizza box. The system was installed by the wireless equipment maker
Qualcomm inside the jet.

The picocell linked to several antennas inside a cable that gathered signals
from passengers' cellphones and sent them all to a small satellite dish, no
bigger than a laptop computer, on top of the plane. From there, the calls
were beamed to an orbiting satellite, which sent the calls back to special
cell stations linked to phone networks on earth.

"It's only a matter of time before we have cellphones on planes," said Scott
Becker, senior vice president of Qualcomm's Wireless Systems division.