Thanks very much for a comprehensive answer! Not many of those are to
be found on usenet.

Lisa wrote:

There is no US FCC regulation against using PCS phones (which do not use the old 800 Mhz
band) in the air. There IS a US FCC regulation against using Part 22 devices in the air,
which would include 800 Mhz AMPS service (traditional analog cellular) as well as newer
digital services in this same band. Sprint and T-Mobile are examples of wireless carriers
which are strictly PCS. Some companies may use both the 800 band and something else. (And
GSM is now starting to be used in the 800 Mhz band in the US, not just in the US 1900 Mhz
band.)

However, the terms of service for each carrier may prohibit airborne operation.