The old North Central Airlines moved up to dc-9’s, though I can still remember their prop-jobs flying overhead(Convair 580’s?). When Northwest took over one of their aircraft acquisitions was an MD-82, not sure how many they acquired but do remember the tragic NW Flt.255 was still painted with the North Central livery(though with Northwest title).
“The old North Central Airlines moved up to dc-9’s, though I can still remember their prop-jobs flying overhead(Convair 580’s?).”
Same here in the west but with Bonanza Airlines Fairchild
F-27’s being supplemented with dc-9’s. Bonanza merged into Air West then Hughes Air West then Republic then Northwest and now Delta.