That is a pipe dream that will never happen. The UA flight attendants will not allow a wholly owned regional. It has been in their contract since the 80's I believe.
2 . Without limiting the foregoing, the Company agrees not to establish or purchase an alter-ego airline in whole or in part .
Look in loa 25 for the full language.
http://unitedafa.org/contract/2016-2...jcba-final.pdf
The FA union made some cash back in the day because UA bought Air whiskey at one point.
https://www.ainonline.com/aviation-n...cope-violation