So as I explained when I first posted the originals, I was inspired to do this from my dad's model railroad company, that is itself, what-if/AU, with strict rules of era based stuff. So, without further adieu, the History of the Olympic Northern Airlines:
The Boeing 247, used from 1949-1959 for short range travel, also used for smaller airports and airfields:
The Douglas DC-3, used from 1949-1962 for medium range travel, also used on smaller airports and airfields:
The Douglas DC-4, used from 1949-1968 for medium range travel:
The Lockheed Constellation, used from 1949-1964 for medium to long range travel:
Holding spot
The Boeing 707, used from 1960-1985, replaced the Lockheed Constellation for medium to long range travel:
The Boeing 737-200, used from 1968-1985, for short to medium range travel, replaced DC-4 for short and medium range travel:
The Boeing 737-300, used from 1982-2008, for short and medium range travel:
The Boeing 737-400, used from 1989-2011, for short to medium range popular routes:
The Boeing 737-500, used from 1990-2010, for short to medium range travel, phased out by 737-600's:
The Boeing 737-600, used from 1998-Current, for short, medium and long range travel:
50th Anniversary, 1949-1999:
Standard Scheme:
Also used but not started on yet (including drawn) Boeing 727, Boeing 757, Boeing 767, Boeing 777 and Boeing 787.