So the BA pilots union didn't have the foresight to negotiate an agreement that would cover all BA operations any where in the world. BA pilots are now threatening to go on strike because this agreement no longer suits them and the BA management wont go back and correct the union's original mistake?
Sounds like a worthy cause.
If OS is like any venture I've ever known then it will have been set up with venture capital supplied by BA. The cost of this capital to OS will probably be around 12%. The aircraft will be leased by OS at market rates, seconded staff will be paid for by OS at market rates, services provided by BA will be contracted at market rates etc.
BA are investing their money to make a return, as all companies do. How do you think the BA pension fund is able to support its members? You don't see BA accountants demanding jobs in FS providers that BA has invested in?