AM & FM differences...still learning after 27 years

I agree with you. There could be any number of reasons why AM is used for some aircraft speech comms (presumably some comms, perhaps data links is digital and they will be using different modulation).

Propagation through the atmosphere (and bouncing off objects!) is a difficult enough concept even without movement, so there may be all sorts of experience with moving aircraft. Even ultra weak AM signals transmitted at low power can be deciphered, who knows if FM receiver techniques have evolved to that level; it may be moot if digital modulation methods are more useful than AM speech for the aviation industry (I've no idea). Anyway, it's possibly a mix of technical reasons, legacy reasons, e.g maybe there's just not a significant enough benefit to switch, and legislation reasons too (available channels and their bandwidth).

I still quite like AM (I reluctantly recently purchased a VHF FM receiver, it is a lot more fun searching AM transmissions on HF; I have a decent receiver for that).. AM is still used worldwide by soldiers too, at HF and VHF. And they also use FM for different purposes. They have loads of experience with the technologies, and they know how to transmit for thousands of miles with AM (usually its sibling, i.e. SSB) using the atmosphere to bounce off (admittedly mostly on HF, so the comparison isn't exactly the same), with just a few Watts of power.

I agree with you. There could be any number of reasons why AM is used for some aircraft speech comms (presumably some comms, perhaps data links is digital and they will be using different modulation).

Propagation through the atmosphere (and bouncing off objects!) is a difficult enough concept even without movement, so there may be all sorts of experience with moving aircraft. Even ultra weak AM signals transmitted at low power can be deciphered, who knows if FM receiver techniques have evolved to that level; it may be moot if digital modulation methods are more useful than AM speech for the aviation industry (I've no idea). Anyway, it's possibly a mix of technical reasons, legacy reasons, e.g maybe there's just not a significant enough benefit to switch, and legislation reasons too (available channels and their bandwidth).

I still quite like AM (I reluctantly recently purchased a VHF FM receiver, it is a lot more fun searching AM transmissions on HF; I have a decent receiver for that).. AM is still used worldwide by soldiers too, at HF and VHF. And they also use FM for different purposes. They have loads of experience with the technologies, and they know how to transmit for thousands of miles with AM (usually its sibling, i.e. SSB) using the atmosphere to bounce off (admittedly mostly on HF, so the comparison isn't exactly the same), with just a few Watts of power.