The RCAF became the launch customer for the new version of the Corvair 540, ordering ten CL-66B variants which incorporated a reinforced floor, wide load doors and the ability for both cargo and passengers. The aircraft were introduced in Air Transport Command and were primarily used for the bulk of the type's career for VIP transport duties. The aircraft were also deployed to Europe for Canadian NATO contingent support as well as to the US in support of Canadian NORAD operations. In 1966, eight of the RCAF CC-109 Cosmopolitans were re-engined with Allison T-56 turboprops. After an avionics upgrade to "glass cockpit" status, the aircraft were retired in 1995.