Airlines don't typically specify a particular manufacturers' aircraft type for their subcontracted commuter carriers, they just specify a certain capability. Especially if they are looking for a "cheap jack", as you describe. I'm pretty sure BA didn't set out to specify the Dornier 328 or the Saab 2000 for their two subcontracted operators who do prop aircraft service into LCY, so unless SAS actually have some financial arrangement with Bombardier I can't see the tie up, or the additional costs that Cityjet will be put to. Given that SAS were probably keen for someone to take Blue1 off their hands, I would have thought the purchaser held all the cards here.