RE: Receivers - Low vrs High
Aircraft use 72Mhz, surface (cars and boats) use 75Mhz, they are on totally different bands. It's not legal to use one for the other.
Btw, the surface radios on 75Mhz usually have a lower power output than aircraft transmitters on 72Mhz. I'm not sure if there is a lower legal limit on the output power, but there might be.