http://thehill.com/regulation/labor/252124-obama-administration-issues-controversial-labor-ruling

This decision by the NLRB seems like it could have massive implications for the regional airline industry if union leaders were to pursue it.

The decision allows that a company who outsources to contractors/franchisees can be considered to be a joint-employer if said company “shares or co-determines those matters governing the essential terms and conditions of employment." And as a result, the primary company can be pulled into collective bargaining negotiations with those outsourced/contracted/franchised employees and held liable for any labor violations committed against them.

I would say that mainline airlines govern some pretty essential terms of regional pilot employment wouldn't you?