Elko, USA
Elko, USA is a city in the U.S. state of Nevada. Probably based on Reno, Elko has low business ratings usually less than 70 but tourism ratings spike in the winter months.
The airport usually isn't open at the start of the game and well into the 1980s. Don't open an airport here, just let the national government open it later on into the game.
Regional routes from San Francisco, Phoenix, or even Denver are profitable assuming you have a monopoly.
Smaller planes are ideal for routes and even the Boeing 737.