I have been trying to figure out how to update icons on the titlebar, but in the meantime I simplified the command to update the title text. If you select the primary title, you do not need that last parameter that says to NOT use the primary title, like this:
PHP Code:
lipc-set-prop com.lab126.chromebar configureChrome '{"titleBar":{"clientParams":{"primary":"Hello \u2708"}}}'
And as you can see, there is a UTF-8 airplane character in the title. Not the same as airplane mode, but there are lots of useful UTF-8 icon characters. That is a start...
Here are some more:
http://csbruce.com/software/utf-8.html