With 2.4GHz, what is the frequency use differentiation of Land (boats) vs Aircraft, or was that only for the old FM technology? In other words, can a 2.4 system be set up for either?

No, they are diff, you buy the one you need, air or surface. Not sure exactly what makes them different, encoding, decoding whatever, but they are diff 2.4 systems, air and surface.


Even among the surface systems, the brands are not generally compatible.