None other than common sense anecdotal evidence. Talk to any ex-XJT currently working at CAL and they will tell you that overall, XJT's work rules are better than CAL's. I know its anecdotal but every one of these people I've talked to say the same thing.

Anyways, for CAL, the IPO wasn't only about doing it cheaper in house. They sold millions of shares of XJT at $15 a share and made a killing while also writing a CPA on XJT's behalf that supposedly created an independent company yet had many strings to restrict what XJT could do and also provided means for lowering the cost of the CPA while holding them hostage if they didn't. And it all happened exactly as planned.

CAL made millions, the other 49% they owned, the slowly sold off to fund their employee pension fund, and they got a XJT to operate so cheap that unless block hours increase, the company loses money.