Maybe I'm putting in the wrong advance routing codes, but I cannot seem to find non-codeshare flights on ITA..

IF I want to fly only AA (no codshares) strict AA metal (is that what it is called?) How/Where is the best way to search??

Or only AA and US and UA, all at the same time, but no codeshares or partners.

Is ITA the best? Only?

What do I put in the advance routing code box??

Thanks to anyone who answers this.