In its time North Central operated Lockheed 10A's, Douglas DC3's, Convair 340/440's which were converted to 580's and Douglas DC9's in the 30 and 50 series.
Here are the aircraft that made up this fleet and where they are (or were at last report).
The files are too large for the layout screen, but if you just right click on the model you want and then open in a new tab you will have the complete file.