Here are four liveries I designed to reflect four eras of livery designs.
The metallic livery in the second diagram reflects the 1940s era. At the beginning of civil aviation era, aircrafts have shiny metal fuselage with thick cheatlines, and stripes on the rudder. The livery is based on the Finnair DC-3 livery.
The second livery, the one in the mid-ground of image 1, reflects the 1960s era. Metal is removed, but cheatline remains to be the key component. I designed this livery with reference to the EG&G livery, but soon realizes that it is almost identical to the 1967 Air Mauritius livery...
The aircraft in the foreground of image 1 reflects the 1990s era. Airlines start to reduce the decorations on the fuselage, some starts to reduce the cheatlines. Inspired by the Continental Global livery.
The black livery (at the back of the first image) reflects modern liveries, with simple to no cheatlines (curved) and black masking. Inspired by the Air Canada black masking.
Simulator: X-Plane 11 by Laminar Research
Aircraft: Fairchild Metroliner III by StarvingPilot (from Org Forum)