With great difficulty. If a transmitter is lonely the CAN silicon will retry the transmission forever. This is actually a useful diagnostic tool on a copper network. In the RF domain it will be like almost continuous carrier, what we call jabbering in network terms. I suppose you have your frequency all to yourself and there is no possibility of interference from other sources. CAN is designed to be a multipoint network, and in the RF domain there is no way to do bitwise arbitration.
You are by no means the first to suggest CAN over RF, but so far there have been no successful implementations that I am aware of.