In the US there was a bunch of regional airlines flying King Airs, SAABs, and the De Havilland Canada Dash 8s. About in the mid 2000s they were retired out in favor for the reginal jets. The reasons being, too loud for customers, some bad winter time accidents, and aging out. Interesting one of the reasons US airspace getting crowded, regional jets can fly with the big boys making routing easier.