The old management at WS would have ensured it was Tim Horton's even if the price was not as good as McD's. Tim's is more fitting the WS image and more likely the go-to coffee of most of its customers. Of course, Tim's has been reluctant to sell to airlines before because it felt it could not be prepared at high altitudes to the same consistent quality since the water would not boil at the high temperature demanded. Inflight coffee machines have improved in that regard.

Next logical step would be to have McD's cater the BoB items, but IIRC WS doesn't have ovens so that's unlikely since most McD items would have to be heated.