CAL's scope clause allows "small jets" of FAA certification up to 50 seats and "small turboprops" of FAA certification up to 79 seats. If it's over 79 seats then CAL mainline pilots would fly it.

CAL is also limited (generally) to a maximum of 274 small jets (which is why ExpressJet has that number). Because CAL mainline is currently operating more than 348 aircraft at the moment (I think the count is about 370), they are allowed to operate more small jets, currently up to approximately 350, if they choose too. The formulas are specified in the CBA. The CBA does not contain limitations on the number of small turboprops that the company can contract for with express carriers. Pinnacle/Colgan currently has plans for a total of 60 Q400's for CAL service.