They're probably the next poor sods to be suckered into flying for SAS thinking it's a great deal. SAS like to have more than one provider but the income and costs of many who have tried to make it work over the years have always been mismatched. JetTime, CityJet, Cimber, Flybe... it's not a happy place to be. And I'm sure I've missed a few off that list.
Good luck to Mesa.