I might misunderstand your question, so just to be clear.
You want to be able to go to 192.168.x.x not on AirVPN while still being connected to AirVPN?
Yes. And the 192.168.x.x addresses will be provided via another OpenVPN connection.
192.168.0.0/16 is a private subnet. Devices already in the subnet are already in your private network, it would make no sense and it is would be also very challenging to route the local traffic onto the Internet just to receive it back in the very same private network. Why should you want to make a packet for your printer travel thousands of miles when it can travel a few meters and remain not exposed on the Internet?
If you mean, instead, that you want to access your local network from the Internet, and therefore create a VPN to share devices and resources which are inside your local network from external devices in a secured environment, then you need to setup a VPN server, so that all the devices (inside and outside your physical local network) will be connected to the same virtual private network... but this has little or nothing to do with AirVPN.