Why can't you use a 72 mhz frequency on the ground for r/c toys? why is it only for r/c aircraft?

Question

why can't you use a 72 mhz frequency on the ground for r/c toys? why is it only for r/c aircraft?

Answer 1

it is because an r/c aircraft has a longer range and its not catchable but a 48 Mhz is more for an r/c race car

Answer 2

This has to do with frequency control.

The frequencies assigned to the RC hobby are segregated between land and air to help prevent unwanted interference.

At organized RC aircraft fields, there is a method to control who turns on transmitters on a specific frequency.  This is important, because if one pilot was flying, and another pilot on the same frequency turned on his transmitter, it could cause the plane to crash.  This control method works well, but only for those who are physically at the field.

If someone running a RC car a block away was on the same frequency, he would have no way of knowing that a particular frequency was in use, and turning on his RC car transmitter could cause that crash.

As such, RC cars are kept on different frequency bands.

Note that this issue is slowly going away, as new 2.4 gigahertz transmitters detect which frequencies are in use and switch to unused frequencies.