In the now obsolete aircraft that I once worked on category is the DC-8 for UPS (United Parcel Service).
In 1980 UPS opened its first major hub in Louisville, Kentucky and began acquiring recently retired commercial jet aircraft. These Douglas DC-8s, Boeing 727-100s and Boeing 747-100s were converted from passenger aircraft to freighters. Of 556 DC-8 aircraft manufactured from 1958 to 1972, around 200 were still in commercial service in 2002, mostly used as freighters and nearly half (97) operated by UPS.
I worked with a team of electrical, systems and structural engineers on a multi-faceted project including an instrument panel re-design, and cabin and service bay modifications.
By 2009, UPS had retired their fleet due to aging, increasing operating costs and strict noise and emissions regulations. The UPS DC-8 final flight landed at Louisville International Airport on May 11, 2009. The first flight of a UPS DC-8 had occurred 21 years prior, on February 1, 1988.