With earlier conventional radios, various bands were allocated for surface or air use. At best, it was bad manners to use the wrong one. At worse, illegal and dangerous.
Not a problem with 2.4GHz, the only problems are that "park flyer" radios often lack the range required, and, since aircraft dominate the market, much of the control labeling is inappropriate. The instructions for my set say that used in air, range is about 1K, on surface, about half that. This assumes that the RX antenna has been sensibly sited.
To reverse a brushless motor it just needs two of the wires to be reversed (any two). A DPDT relay worked by a switcher would do the job, but it would need some sort of interlock to prevent the possibility of just slamming it into reverse. A "proper" ESC that changes the phase order for reverse is a much neater idea, and they are available. Being for a smaller market, they do tend to cost more than a similar power forward only type.