Whose name was on the outside of the aircraft? Whose logo was on the seats - napkins - uniforms?
Republic is a regional carrier. They also serve Dalta and American Airlines. Their planes are also painted with “Delta: and “American,” but Republic Airways owns the planes, and the company is is managed by Republic Airways. They have their own pilots, gate agents, flight attendants, etc.
Republic Airways:
https://en.wikipedia.org/wiki/Republic_Airways_Holdings
Republic Airways CEO and Leadership:
http://www.rjet.com/Who_We_Are/Leadership.aspx
Republic Airways is to blame:
http://www.foxbusiness.com/features/2017/04/13/republic-airlines-is-to-blame-for-united-airlines-incident-former-spirit-airlines-ceo.html