Airio is only for servers. I think you are asking about a local client thing. In that case no, LFS's chat system doesn't support using variables like that.
One workaround for displaying the current car message would be using LFS script system. Every time you join, leave garage or reset car an appropriate script is triggered. If you are for example in XRG then "C:\LFS\data\script\XRG.lfs" script is triggered and all commands inside this script file are executed. There is also a command (
/altf and
/ctrlf) to change text of a specific key combo so you can use this command with the script system to create kind of a switch or whatever you would call it.
So let's say you want CTRL+F1 to display the current car message. You add these commands to every single CAR.lfs script (you can edit these scripts using Notepad or any other text editor) but for each car the text will be different (obviously).
In
XRG.lfs you add this line
/ctrlf 1 My car is XRG
In
XFG.lfs you add this line
/ctrlf 1 My car is XFG
and so on..
Then if you press CTRL+F1 it should send the message you want.
There is no command to change text of F1-F8 keys (without Ctrl or Alt) but if you still want to trigger that message with single F key then you can use command
/ctrl F1 (this is different than the
/ctrlf command!!) to simulate pressing Ctrl+F1. Just bind this command as normal text to whatever F key you want to use.
You can check "C:\LFS\docs\Commands.txt" for more info.
But yeah, this workaround is only useful for the current car message. For displaying tracks and other stuff you would need a local InSim app.