Short Brothers of Belfast, Northern Ireland took their rugged Skyvan and developed it into the perfect 'high capacity' (for the time) commuter airline just as deregulation sent the third level airlines into expansion overdrive. The Shorts Sheds (as the 330 and later 360 became known) were the cream of commuter aircraft into the early 1980s when a few regional airlines had grown large enough to operate what had been mainline types, like the F-27 and CV-580, or large converted executive types, like the Gulfstream 1.
Simmons began operations in 1978, using a Piper Navajo, and grew to become one of the largest commuters in the USA by the early 1990s. Its first franchise agreement was with Republic Airlines in April 1985 operating from Detroit, but this soon became Northwest Airlink when Republic was taken over. It also operated for American from Chicago since October 1985. When American purchased Simmons in August 1987 flights for Northwest ceased. The airline built up the largest fleet of Shorts 360s in the world after taking its first aircraft in June 1983.
Simmons itself survived until May 1998 when American Airlines completed the amalgamation of all its Eagle commuter airlines (except San Juan based Executive Airlines) under Simmons AOC and renamed the resulting airline American Eagle Airlines.