First off, this is not so much an issue of different mobile generations such as 5G or 4G but rather the frequencies in use. Aircraft altimeters operate in a frequency range of between 4.2 and 4.4 GHz. In the US, 5G technology has been authorised to operate in the 3.75-3.98 Ghz frequency range, giving rise to fears that it could interfere with aircraft radio altimeters. Of course, it is not for Swisscom to assess the situation in the US. According to the Federal Office of Civil Aviation, no interference has occurred to date in this country and the situation in Switzerland is not comparable to that in the US. The Federal Office of Civil Aviation (FOCA) states that, to date, there have been no incidents recorded anywhere in the world in which 5G masts have led to the impairment of aircraft safety functions.
 Federal Office of Communications
 Federal Office of Civil Aviation